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in this link you can download the lecture notes and questions paper of different program........... specially for the engineering students,,
thank you for post visit....!!!
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Wednesday, 10 April 2013
16:58
Unknown
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Monday, 5 December 2011
06:03
Unknown
How to install Turbo C in Window 7
Most of you guys are probably being exhausted from installing Turbo C program in Window 7 64 bit and 32 bit. Most have commented that in Window 7 Turbo C doesn't get supported. If in case supported full screen doesn't appear. Now don't feel so friends! because here is the solution. Simply you can install it. What you have to do is just click the following link and get
Download Latest Version of Turbo C 3.0.7 Beta for Windows 7
OR just follow the link below and download turbo c directly.
http://www.mediafire.com/error.php?errno=320
After you download, the downloaded files get saved directly in C drive of your computer.
Most of you guys are probably being exhausted from installing Turbo C program in Window 7 64 bit and 32 bit. Most have commented that in Window 7 Turbo C doesn't get supported. If in case supported full screen doesn't appear. Now don't feel so friends! because here is the solution. Simply you can install it. What you have to do is just click the following link and get
Download Latest Version of Turbo C 3.0.7 Beta for Windows 7
OR just follow the link below and download turbo c directly.
http://www.mediafire.com/error.php?errno=320
After you download, the downloaded files get saved directly in C drive of your computer.
Monday, 11 January 2010
00:45
Unknown
Technology
The Bank believes that advancement in technology
should be used towards enhancing the quality of
customer service. In line with this approach we
installed our own switching system that will enhance
our service delivery quality especially in the area of
plastic cards which in turn will provide us with new
and increased source of revenue.
The Bank also expects the Switching Platform to
play an important role in terms of introducing other
technologically driven services in the future.
Remittances
Continuing the trend of year-on-year increase, the
country received total remittances of NPR 142.68
billion during the year, an increase of 42.5% over
the previous year. Given the strong opportunities
presented by the sector the Bank continued to
strengthen our presence in this business especially in
the Gulf and Malaysian corridors. The Bank continues
to maintain representatives in the UAE who are
responsible for business development and client
servicing. We have established ourselves as one of
the leading Banks in this business supported by a
growing network of Payout Agents reaching many
rural areas of all major districts in the country.
The Bank believes that advancement in technology
should be used towards enhancing the quality of
customer service. In line with this approach we
installed our own switching system that will enhance
our service delivery quality especially in the area of
plastic cards which in turn will provide us with new
and increased source of revenue.
The Bank also expects the Switching Platform to
play an important role in terms of introducing other
technologically driven services in the future.
Remittances
Continuing the trend of year-on-year increase, the
country received total remittances of NPR 142.68
billion during the year, an increase of 42.5% over
the previous year. Given the strong opportunities
presented by the sector the Bank continued to
strengthen our presence in this business especially in
the Gulf and Malaysian corridors. The Bank continues
to maintain representatives in the UAE who are
responsible for business development and client
servicing. We have established ourselves as one of
the leading Banks in this business supported by a
growing network of Payout Agents reaching many
rural areas of all major districts in the country.
Tuesday, 11 August 2009
05:50
Unknown
The Computer History Museum
Background
The Computer History Museum was formally established as a non-profit 501(c)(3) organization in 1999. The Museum is dedicated to the preservation and celebration of computing history. We are home to one of the largest international collections of computing artifacts in the world, encompassing physical objects, ephemera, photographs, moving images, documents and software.
In 1979, the Museum's founders Gordon and Gwen Bell opened an exhibit of many computing devices from their personal collection in the lobby of Digital Equipment Corporation. It wasn't long afterward that the Museum's name became The Digital Computer Museum and subsequently The Computer Museum.
In the fall of 1984, The Computer Museum opened to the public at Museum Wharf in Boston, sharing space with the Children's Museum. The Museum focused on computing history lectures, exhibiting highlights of the collection, and many children's educational activities including a two-story walk through computer, a virtual fish tank and a robot theatre.
In 1996, a significant portion of the Museum's collection moved to Mountain View, California. California was seen as an ideal place for an emphasis on collecting and the preservation of the Museum's growing collection. In Boston, the focus continued on exhibits. By 2000 the remaining collection from Boston arrived in Silicon Valley.
In 2001, the Museum shortened its name from The Computer Museum History Center to our current name. The next year, we moved into our permanent home with the purchase of a landmark building on Shoreline Boulevard in Mountain View. We currently have on-site three exhibits Visible Storage: Samples from the Collection, Mastering the Game: A History of Computer Chess and Innovation 101.
Under construction is the Museum's signature exhibit entitled "Computer History: the First 2000 years" due to open in late 2010.
Tours and Hours of Operation
The Museum's "Visible Storage" exhibit area is open for docent-led tours every week. Self-guided tours are also available in "Visible Storage" and the Museum's other two exhibits, "Innovation in the Valley" and "Mastering the Game: A History of Computer Chess." Tours are free and hours of operation are located on the Museum's website. Groups of 10 or more should call in advance to 650-810-1038 or e-mail tours@computerhistory.org.
Education
The Computer History Museum offers lectures, seminars and workshops with scholarly historical perspectives about and by the pioneers of the computing industry. The Museum's emphasis on preservation and education make it a unique resource for media researchers, historians, scientists, industry professionals and students of all ages. Research services are available to scholars by staff researchers as well as through the Museum's comprehensive website.
Lectures and Events
The Museum is proud to host monthly lectures with leading innovators; industry giants and opinion leaders; experts; engineers and scientists who share their personal stories and insights about developments, events and discoveries that have shaped our world. The Museum also frequently hosts other significant events that highlight and honor the history of computing and celebrate major industry milestones as they occur.
Fellow Awards
Each year over the past twenty years, the Museum has honored computing pioneers at an annual Fellow Awards Celebration. Museum Fellows are individuals who have made revolutionary and lasting contributions to the development of computing and often present a lecture or conduct a workshop and oral histories in connection with the awards program.
Publications
Articles about industry leaders and computing breakthroughs appear in the Museum's annual spring publication, Core, and the Museum's staff also publishes articles with both technical and historical content in complementary journals and magazines.
Future Plans
The Computer History Museum's efforts are underway to further expand its home in Silicon Valley. Future plans include additional and changing exhibits as well as theme rooms. Next up for spring 2008 is the debut of the Babbage Difference Engine #2, an extraordinary Victorian era computing device that no Victorian ever saw! It was finally built 153 years after Charles Babbage's (1791-1871) original design, and is rich in history. And then there is the Museum's 14,000 square-foot major and signature exhibit, the "Timeline of Computing History" due to open in the fall of 2009.
Background
The Computer History Museum was formally established as a non-profit 501(c)(3) organization in 1999. The Museum is dedicated to the preservation and celebration of computing history. We are home to one of the largest international collections of computing artifacts in the world, encompassing physical objects, ephemera, photographs, moving images, documents and software.
In 1979, the Museum's founders Gordon and Gwen Bell opened an exhibit of many computing devices from their personal collection in the lobby of Digital Equipment Corporation. It wasn't long afterward that the Museum's name became The Digital Computer Museum and subsequently The Computer Museum.
In the fall of 1984, The Computer Museum opened to the public at Museum Wharf in Boston, sharing space with the Children's Museum. The Museum focused on computing history lectures, exhibiting highlights of the collection, and many children's educational activities including a two-story walk through computer, a virtual fish tank and a robot theatre.
In 1996, a significant portion of the Museum's collection moved to Mountain View, California. California was seen as an ideal place for an emphasis on collecting and the preservation of the Museum's growing collection. In Boston, the focus continued on exhibits. By 2000 the remaining collection from Boston arrived in Silicon Valley.
In 2001, the Museum shortened its name from The Computer Museum History Center to our current name. The next year, we moved into our permanent home with the purchase of a landmark building on Shoreline Boulevard in Mountain View. We currently have on-site three exhibits Visible Storage: Samples from the Collection, Mastering the Game: A History of Computer Chess and Innovation 101.
Under construction is the Museum's signature exhibit entitled "Computer History: the First 2000 years" due to open in late 2010.
Tours and Hours of Operation
The Museum's "Visible Storage" exhibit area is open for docent-led tours every week. Self-guided tours are also available in "Visible Storage" and the Museum's other two exhibits, "Innovation in the Valley" and "Mastering the Game: A History of Computer Chess." Tours are free and hours of operation are located on the Museum's website. Groups of 10 or more should call in advance to 650-810-1038 or e-mail tours@computerhistory.org.
Education
The Computer History Museum offers lectures, seminars and workshops with scholarly historical perspectives about and by the pioneers of the computing industry. The Museum's emphasis on preservation and education make it a unique resource for media researchers, historians, scientists, industry professionals and students of all ages. Research services are available to scholars by staff researchers as well as through the Museum's comprehensive website.
Lectures and Events
The Museum is proud to host monthly lectures with leading innovators; industry giants and opinion leaders; experts; engineers and scientists who share their personal stories and insights about developments, events and discoveries that have shaped our world. The Museum also frequently hosts other significant events that highlight and honor the history of computing and celebrate major industry milestones as they occur.
Fellow Awards
Each year over the past twenty years, the Museum has honored computing pioneers at an annual Fellow Awards Celebration. Museum Fellows are individuals who have made revolutionary and lasting contributions to the development of computing and often present a lecture or conduct a workshop and oral histories in connection with the awards program.
Publications
Articles about industry leaders and computing breakthroughs appear in the Museum's annual spring publication, Core, and the Museum's staff also publishes articles with both technical and historical content in complementary journals and magazines.
Future Plans
The Computer History Museum's efforts are underway to further expand its home in Silicon Valley. Future plans include additional and changing exhibits as well as theme rooms. Next up for spring 2008 is the debut of the Babbage Difference Engine #2, an extraordinary Victorian era computing device that no Victorian ever saw! It was finally built 153 years after Charles Babbage's (1791-1871) original design, and is rich in history. And then there is the Museum's 14,000 square-foot major and signature exhibit, the "Timeline of Computing History" due to open in the fall of 2009.
Wednesday, 5 August 2009
04:21
Unknown
Keystroke logging
Keystroke logging (often called keylogging) is the practice of noting (or logging) the keys struck on a keyboard, typically in a covert manner so that the person using the keyboard is unaware that their actions are being monitored. There are numerous keylogging methods, ranging from hardware- and software-based to electromagnetic and acoustic analysis.
[edit] Application
[edit] Software-based keyloggers
These are software programs that are designed to work on the target computer’s operating system. From a technical perspective there are four categories:
Hypervisor-based: The keylogger can theoretically reside in a malware hypervisor running underneath the operating system, which remains untouched, except that it effectively becomes a virtual machine. See Blue Pill for a conceptual example.
Kernel based: This method is difficult both to write and to combat. Such keyloggers reside at the kernel level and are thus difficult to detect, especially for user-mode applications. They are frequently implemented as rootkits that subvert the operating system kernel and gain unauthorized access to the hardware which makes them very powerful. A keylogger using this method can act as a keyboard driver for example, and thus gain access to any information typed on the keyboard as it goes to the operating system.
Hook based: Such keyloggers hook the keyboard using functionality provided by the operating system for applications to subscribe to keyboard events legitimately. The operating system notifies the keylogger each time a key is pressed and the keylogger simply records it.
Passive Methods: Here the coder uses operating system APIs like GetAsyncKeyState(), GetForegroundWindow(), etc. to poll the state of the keyboard or to subscribe to keyboard events. These are the easiest to write, but where constant polling of each key is required, they can cause a noticeable increase in CPU usage and can miss the occasional key. A more recent example simply polls the BIOS for preboot authentication PINs that have not been cleared from memory.
Form Grabber based logs web form submissions by recording the web browsing .onsubmit event functions. This records form data before it is passed over the internet and bypasses https encryption.
Remote access software keyloggers
These are local software keyloggers programmed with an added feature to transmit recorded data out of the target computer and make the data available to the monitor at a remote location. Remote communication is facilitated by one of four methods:
Data is uploaded to a website or an ftp account.
Data is periodically emailed to a pre-defined email address.
Data is wirelessly transmitted by means of an attached hardware system.
It allows the monitor to log into the local machine via the internet or ethernet and access the logs stored on the target machine.
Related Features
Software Keyloggers may be augmented with features that capture user information without relying on keyboard key presses as the sole input. Some of these features include:
Clipboard logging. Anything that has been copied to the clipboard can be captured by the program.
Screen logging. Screenshots are taken in order to capture graphics-based information. Applications with screen logging abilities may take screenshots of the whole screen, just one application or even just around the mouse. They may take these screenshots periodically or in response to user behaviours (for example, when a user has clicked the mouse). A practical application used by some keyloggers with this screen logging ability is to take small screenshots around where a mouse has just clicked; these defeat web-based keyboards (for example, the web-based screen keyboards that are often used by banks) and any web-based on-screen keyboard without screenshot protection.
Programmatically capturing the text in a control. The Microsoft Windows API allows programs to request the text 'value' in some controls. This means that some passwords may be captured, even if they are hidden behind password masks (usually asterisks).[2]
Hardware-based keyloggers
Main article: Hardware keylogger
Hardware-based keyloggers do not depend upon any software being installed as they exist at a hardware level in a computer system.
Firmware-based: BIOS-level firmware that handles keyboard events can be modified to record these events as they are processed. Physical access or root-level access is required to machine, and the software loaded into the BIOS needs to be created for the specific hardware that it will be running on.
Keyboard hardware: Hardware keyloggers are used for keystroke logging by means of a hardware circuit that is attached somewhere in between the computer keyboards and the computer, typically inline with the keyboard's cable connector. More stealthy implementations can be installed or built into standard keyboards, so that there's no device visible on the external cable. Both types logs all keyboard activity to their internal memory, which can subsequently be accessed, for example, by typing in a secret key sequence.[3] A hardware keylogger has an advantage over a software solution; because it is not dependent on installation on the target computer's operating system, it will not interfere with any program running on the target machine and also cannot be detected by any software. However its physical presence may be detected, for example if it's installed outside the case as an inline device between the computer and the keyboard. Some of these implementations have the ability to be controlled and monitored remotely by means of a wireless communication standard.[citation needed]
Wireless keyboard sniffers
These are passive sniffers collect packets of data being transferred from a wireless keyboard and its receiver. As encryption may be used to secure the wireless communications between the two devices, this may need to be cracked before if the transmissions are to be read.
Keyboard overlays
Criminals have been known to use keyboard overlays on ATM machines to capture people's PINs. Each keypress is registered by the keyboard of the ATM as well as the criminal's keypad that is placed over it. The device is designed to look like an integrated part of the machine so that bank customers are unware of its presence.
Acoustic keyloggers
Acoustic cryptanalysis can be used to monitor the sound created by someone typing on a computer. Each character on the keyboard makes a subtly different acoustic signature when stroked. It is then possible to identify which keystroke signature relates to which keyboard character via statistical methods such as frequency analysis. The repetition frequency of similar acoustic keystroke signatures, the timings between different keyboard strokes and other context information such as the probable language in which the user is writing are used in this analysis to map sounds to letters. A fairly long recording (1000 or more keystrokes) is required so that a big enough sample is collected.[citation needed]
Electromagnetic emissions
It is possible to capture the electromagnetic emissions of a keyboard, without being physically wired to it.
Optical surveillance
Not a keylogger in the classical sense, but an approach that can nonetheless be used to capture passwords or PINs. A strategically placed camera, such as a hidden surveillance camera at an ATM, can allow a criminal to watch a PIN or password being entered.
Cracking
Writing software applications for keylogging is trivial,[citation needed] and like any nefarious computer program, can be distributed as a trojan horse or as part of a virus. What is not trivial for an attacker however, is installing a covert keystroke logger without getting caught and downloading data that has been logged without being traced. An attacker that manually connects to a host machine to download logged keystrokes risks being traced. A trojan that sends keylogged data to a fixed e-mail address or IP address risks exposing the attacker.
Trojan
Young and Yung devised several methods for solving this problem and presented them in their 1997 IEEE Security & Privacy paper (their paper from '96 touches on it as well). They presented a deniable password snatching attack in which the keystroke logging trojan is installed using a virus (or worm). An attacker that is caught with the virus or worm can claim to be a victim. The cryptotrojan asymmetrically encrypts the pilfered login/password pairs using the public key of the trojan author and covertly broadcasts the resulting ciphertext. They mentioned that the ciphertext can be steganographically encoded and posted to a public bulletin board (e.g. Usenet).
Ciphertext
Young and Yung also mentioned having the cryptotrojan unconditionally write the asymmetric ciphertexts to the last few unused sectors of every writable disk that is inserted into the machine. The sectors remain marked as unused. This can be done using a USB token. So, the trojan author may be one of dozens or even thousands of people that are given the stolen information. Only the trojan author can decrypt the ciphertext because only the author knows the needed private decryption key. This attack is from the field known as cryptovirology.
Federal Bureau of Investigation
In 2000, the FBI used a keystroke logger to obtain the PGP passphrase of Nicodemo Scarfo, Jr., son of mob boss Nicodemo Scarfo.
Use in surveillance software
Some surveillance software has keystroke logging abilities and is advertised to monitor the internet use of minors. Such software has been criticized on privacy grounds, and because it can be used maliciously or to gain unauthorized access to users' computer systems.
Countermeasures
Countermeasures against keyloggers will vary depending on the type of keylogger in use.
Code signing
64-bit versions of Windows Vista and Server 2008 implement mandatory digital signing of kernel-mode device drivers, thereby restricting the installation of key-logging rootkits.
Anti-spyware
Many anti-spyware applications are able to detect keyloggers and quarantine, disable or cleanse them. These applications are able to detect keyloggers based on patterns in executable code, heuristics and keylogger behaviours (such as the use of hooks and certain APIs).
No software-based anti-spyware application can be 100% effective against all keyloggers. Also, software-based anti-spyware cannot defeat non-software keyloggers (for example, hardware keyloggers attached to keyboards will always receive keystrokes before any software-based anti-spyware application, rendering the anti-spyware application useless).
However, the particular technique that the anti-spyware application uses will influence its potential effectiveness against software keyloggers. As a general rule, anti-spyware applications with higher privileges (see Ring (computer security)) will defeat keyloggers with lower privileges. For example, a hook-based anti-spyware application cannot defeat a kernel-based keylogger (as the keylogger will receive the keystroke messages before the anti-spyware application), but it could potentially defeat hook and API-based keyloggers.
Firewall
Enabling a firewall does not stop keyloggers per se, but can prevent the remote installation of key logging software, and possibly prevent transmission of the logged material over the internet if properly configured.
Network monitors
Network monitors (also known as reverse-firewalls) can be used to alert the user whenever an application attempts to make a network connection. This gives the user the chance to prevent the keylogger from "phoning home" with his or her typed information.
Automatic form filler programs
Automatic form-filling programs may prevent keylogging by removing the requirement for a user to type personal details and passwords using the keyboard. Form fillers are primarily designed for web browsers to fill in checkout pages and log users into their accounts. Once the user's account and credit card information has been entered into the program, it will be automatically entered into forms without ever using the keyboard or clipboard, thereby reducing the possibility that private data is being recorded. However someone with physical access to the machine may still be able to install software that is able to intercept this information elsewhere in the operating system or while in transit on the network. (Transport Layer Security prevents the interception of data in transit by network sniffers and proxy tools.)
Alternative keyboard layouts
Most keylogging hardware/software assumes that a person is using the standard QWERTY keyboard layout, so by using a layout such as Dvorak, frequency analysis is required to determine the mapping of captured keystrokes. For additional security, custom keyboard layouts can be created using tools like the Microsoft Keyboard Layout Creator.
One-time passwords (OTP)
Using one-time passwords is completely keylogger-safe because the recorded password is always invalidated as soon as it's used. This solution is useful if you are often using public computers where you can't verify what is running on them. One-time passwords also prevent replay attacks where an attacker uses the old information to impersonate. One example is online banking where one-time passwords are implemented to protect accounts from keylogging attacks as well as replay attacks.
Smart cards
Because of the integrated circuit of smart cards, the cards themselves are not affected by keylogger and other logging attempts. A smart card can process the information and return back a unique challenge every time you login. The information cannot usually be used to login again. However smartcard readers and their associated keypads for PIN entry are still vulnerable to key logging.
On-screen keyboards
Program-to-program (non-web) keyboards
It is sometimes said that a third-party (or first party) on-screen keyboard program is a good way to combat keyloggers, as it only requires clicks of the mouse. However, this is not always true.
Most on screen keyboards (such as the onscreen keyboard that comes with Microsoft Windows XP) send keyboard event messages to the external target program to type text. Every software keylogger can log these typed characters sent from one program to another. Additionally, some programs also record or take snapshots of what is displayed on the screen (periodically, and/or upon each mouse click).
However, there are some on-screen keyboard programs that do offer some protection, using other techniques described in this article (such as dragging and dropping the password from the on-screen keyboard to the target program).
Web-based keyboards
Web-based on-screen keyboards (written in JavaScript, etc.) may provide some degree of protection. At least some commercial keylogging programs do not record typing on a web-based virtual keyboard. (Screenshot recorders are a concern whenever entire passwords are displayed; fast recorders are generally required to capture a sequence of virtual key presses.)
Notably, the game MapleStory uses, in addition to a standard alphanumeric password, a 4-digit PIN code secured by both on-screen keyboard entry and a randomly changing button pattern; there is no real way to get the latter information without logging the screen and mouse movements; another MMORPG called RuneScape makes a similar system available for players to protect their in-game bank accounts.
Many banks uses the web-based screen keyboard to prevent key logging. HSBC is one of them.
Anti-keylogging software
Keylogger detection software is also available. Some of this type of software use "signatures" from a list of all known keyloggers. The PC's legitimate users can then periodically run a scan from this list, and the software looks for the items from the list on the hard-drive. One drawback of this approach is that it only protects from keyloggers on the signature-based list, with the PC remaining vulnerable to other keyloggers.
Other detection software doesn't use a signature list, but instead analyzes the working methods of many modules in the PC, allowing it to block the work of many different types of keylogger. One drawback of this approach is that it can also block legitimate, non-keylogging software. Some heuristics-based anti-keyloggers have the option to unblock known good software, but this can cause difficulties for inexperienced users.
Speech recognition
Similar to on-screen keyboards, speech-to-text conversion software can also be used against keyloggers, since there are no typing or mouse movements involved. The weakest point of using voice-recognition software may be how the software sends the recognized text to target software after the recognition took place.
Handwriting recognition and mouse gestures
Also, many PDAs and lately Tablet PCs can already convert pen (also called stylus) movements on their touchscreens to computer understandable text successfully. Mouse gestures utilize this principle by using mouse movements instead of a stylus. Mouse gesture programs convert these strokes to user-definable actions, among others typing text. Similarly, graphics tablets and light pens can be used to input these gestures, however, these are getting used less commonly everyday.
The same potential weakness of speech recognition applies to this technique as well.
Macro expanders/recorders
With the help of many Freeware/Shareware programs, a seemingly meaningless text can be expanded to a meaningful text and most of the time context-sensitively, e.g. "we" can be expanded "en.Wikipedia.org" when a browser window has the focus. The biggest weakness of this technique is that these programs send their keystrokes directly to the target program. However, this can be overcome by using the 'alternating' technique described below, i.e. sending mouse clicks to non-responsive areas of the target program, sending meaningless keys, sending another mouse click to target area (e.g. password field) and switching back and forth.
Window transparency
Using many readily available utilities, the target window could be made temporarily transparent, in order to hinder screen-capturing by advanced keyloggers.[citation needed] Although not a fool-proof technique against keyloggers on its own, this could be used in combination with other techniques.
Non-technological methods
Some keyloggers can be fooled by alternating between typing the login credentials and typing characters somewhere else in the focus window. Similarly, a user can move their cursor using the mouse during typing, causing the logged keystrokes to be in the wrong order e.g. by typing a password beginning with the last letter and then using the mouse to move the cursor for each subsequent letter. Lastly, someone can also use context menus to remove, copy, cut and paste parts of the typed text without using the keyboard.
Another very similar technique utilizes the fact that any selected text portion is replaced by the next key typed. E.g. if the password is "secret", one could type "s", then some dummy keys "asdfsd". Then these dummies could be selected with mouse, and next character from the password "e" is typed, which replaces the dummies "asdfsd".
[edit] Software-based keyloggers
These are software programs that are designed to work on the target computer’s operating system. From a technical perspective there are four categories:
Hypervisor-based: The keylogger can theoretically reside in a malware hypervisor running underneath the operating system, which remains untouched, except that it effectively becomes a virtual machine. See Blue Pill for a conceptual example.
Kernel based: This method is difficult both to write and to combat. Such keyloggers reside at the kernel level and are thus difficult to detect, especially for user-mode applications. They are frequently implemented as rootkits that subvert the operating system kernel and gain unauthorized access to the hardware which makes them very powerful. A keylogger using this method can act as a keyboard driver for example, and thus gain access to any information typed on the keyboard as it goes to the operating system.
Hook based: Such keyloggers hook the keyboard using functionality provided by the operating system for applications to subscribe to keyboard events legitimately. The operating system notifies the keylogger each time a key is pressed and the keylogger simply records it.
Passive Methods: Here the coder uses operating system APIs like GetAsyncKeyState(), GetForegroundWindow(), etc. to poll the state of the keyboard or to subscribe to keyboard events. These are the easiest to write, but where constant polling of each key is required, they can cause a noticeable increase in CPU usage and can miss the occasional key. A more recent example simply polls the BIOS for preboot authentication PINs that have not been cleared from memory.
Form Grabber based logs web form submissions by recording the web browsing .onsubmit event functions. This records form data before it is passed over the internet and bypasses https encryption.
Remote access software keyloggers
These are local software keyloggers programmed with an added feature to transmit recorded data out of the target computer and make the data available to the monitor at a remote location. Remote communication is facilitated by one of four methods:
Data is uploaded to a website or an ftp account.
Data is periodically emailed to a pre-defined email address.
Data is wirelessly transmitted by means of an attached hardware system.
It allows the monitor to log into the local machine via the internet or ethernet and access the logs stored on the target machine.
Related Features
Software Keyloggers may be augmented with features that capture user information without relying on keyboard key presses as the sole input. Some of these features include:
Clipboard logging. Anything that has been copied to the clipboard can be captured by the program.
Screen logging. Screenshots are taken in order to capture graphics-based information. Applications with screen logging abilities may take screenshots of the whole screen, just one application or even just around the mouse. They may take these screenshots periodically or in response to user behaviours (for example, when a user has clicked the mouse). A practical application used by some keyloggers with this screen logging ability is to take small screenshots around where a mouse has just clicked; these defeat web-based keyboards (for example, the web-based screen keyboards that are often used by banks) and any web-based on-screen keyboard without screenshot protection.
Programmatically capturing the text in a control. The Microsoft Windows API allows programs to request the text 'value' in some controls. This means that some passwords may be captured, even if they are hidden behind password masks (usually asterisks).[2]
Hardware-based keyloggers
Main article: Hardware keylogger
Hardware-based keyloggers do not depend upon any software being installed as they exist at a hardware level in a computer system.
Firmware-based: BIOS-level firmware that handles keyboard events can be modified to record these events as they are processed. Physical access or root-level access is required to machine, and the software loaded into the BIOS needs to be created for the specific hardware that it will be running on.
Keyboard hardware: Hardware keyloggers are used for keystroke logging by means of a hardware circuit that is attached somewhere in between the computer keyboards and the computer, typically inline with the keyboard's cable connector. More stealthy implementations can be installed or built into standard keyboards, so that there's no device visible on the external cable. Both types logs all keyboard activity to their internal memory, which can subsequently be accessed, for example, by typing in a secret key sequence.[3] A hardware keylogger has an advantage over a software solution; because it is not dependent on installation on the target computer's operating system, it will not interfere with any program running on the target machine and also cannot be detected by any software. However its physical presence may be detected, for example if it's installed outside the case as an inline device between the computer and the keyboard. Some of these implementations have the ability to be controlled and monitored remotely by means of a wireless communication standard.[citation needed]
Wireless keyboard sniffers
These are passive sniffers collect packets of data being transferred from a wireless keyboard and its receiver. As encryption may be used to secure the wireless communications between the two devices, this may need to be cracked before if the transmissions are to be read.
Keyboard overlays
Criminals have been known to use keyboard overlays on ATM machines to capture people's PINs. Each keypress is registered by the keyboard of the ATM as well as the criminal's keypad that is placed over it. The device is designed to look like an integrated part of the machine so that bank customers are unware of its presence.
Acoustic keyloggers
Acoustic cryptanalysis can be used to monitor the sound created by someone typing on a computer. Each character on the keyboard makes a subtly different acoustic signature when stroked. It is then possible to identify which keystroke signature relates to which keyboard character via statistical methods such as frequency analysis. The repetition frequency of similar acoustic keystroke signatures, the timings between different keyboard strokes and other context information such as the probable language in which the user is writing are used in this analysis to map sounds to letters. A fairly long recording (1000 or more keystrokes) is required so that a big enough sample is collected.[citation needed]
Electromagnetic emissions
It is possible to capture the electromagnetic emissions of a keyboard, without being physically wired to it.
Optical surveillance
Not a keylogger in the classical sense, but an approach that can nonetheless be used to capture passwords or PINs. A strategically placed camera, such as a hidden surveillance camera at an ATM, can allow a criminal to watch a PIN or password being entered.
Cracking
Writing software applications for keylogging is trivial,[citation needed] and like any nefarious computer program, can be distributed as a trojan horse or as part of a virus. What is not trivial for an attacker however, is installing a covert keystroke logger without getting caught and downloading data that has been logged without being traced. An attacker that manually connects to a host machine to download logged keystrokes risks being traced. A trojan that sends keylogged data to a fixed e-mail address or IP address risks exposing the attacker.
Trojan
Young and Yung devised several methods for solving this problem and presented them in their 1997 IEEE Security & Privacy paper (their paper from '96 touches on it as well). They presented a deniable password snatching attack in which the keystroke logging trojan is installed using a virus (or worm). An attacker that is caught with the virus or worm can claim to be a victim. The cryptotrojan asymmetrically encrypts the pilfered login/password pairs using the public key of the trojan author and covertly broadcasts the resulting ciphertext. They mentioned that the ciphertext can be steganographically encoded and posted to a public bulletin board (e.g. Usenet).
Ciphertext
Young and Yung also mentioned having the cryptotrojan unconditionally write the asymmetric ciphertexts to the last few unused sectors of every writable disk that is inserted into the machine. The sectors remain marked as unused. This can be done using a USB token. So, the trojan author may be one of dozens or even thousands of people that are given the stolen information. Only the trojan author can decrypt the ciphertext because only the author knows the needed private decryption key. This attack is from the field known as cryptovirology.
Federal Bureau of Investigation
In 2000, the FBI used a keystroke logger to obtain the PGP passphrase of Nicodemo Scarfo, Jr., son of mob boss Nicodemo Scarfo.
Use in surveillance software
Some surveillance software has keystroke logging abilities and is advertised to monitor the internet use of minors. Such software has been criticized on privacy grounds, and because it can be used maliciously or to gain unauthorized access to users' computer systems.
Countermeasures
Countermeasures against keyloggers will vary depending on the type of keylogger in use.
Code signing
64-bit versions of Windows Vista and Server 2008 implement mandatory digital signing of kernel-mode device drivers, thereby restricting the installation of key-logging rootkits.
Anti-spyware
Many anti-spyware applications are able to detect keyloggers and quarantine, disable or cleanse them. These applications are able to detect keyloggers based on patterns in executable code, heuristics and keylogger behaviours (such as the use of hooks and certain APIs).
No software-based anti-spyware application can be 100% effective against all keyloggers. Also, software-based anti-spyware cannot defeat non-software keyloggers (for example, hardware keyloggers attached to keyboards will always receive keystrokes before any software-based anti-spyware application, rendering the anti-spyware application useless).
However, the particular technique that the anti-spyware application uses will influence its potential effectiveness against software keyloggers. As a general rule, anti-spyware applications with higher privileges (see Ring (computer security)) will defeat keyloggers with lower privileges. For example, a hook-based anti-spyware application cannot defeat a kernel-based keylogger (as the keylogger will receive the keystroke messages before the anti-spyware application), but it could potentially defeat hook and API-based keyloggers.
Firewall
Enabling a firewall does not stop keyloggers per se, but can prevent the remote installation of key logging software, and possibly prevent transmission of the logged material over the internet if properly configured.
Network monitors
Network monitors (also known as reverse-firewalls) can be used to alert the user whenever an application attempts to make a network connection. This gives the user the chance to prevent the keylogger from "phoning home" with his or her typed information.
Automatic form filler programs
Automatic form-filling programs may prevent keylogging by removing the requirement for a user to type personal details and passwords using the keyboard. Form fillers are primarily designed for web browsers to fill in checkout pages and log users into their accounts. Once the user's account and credit card information has been entered into the program, it will be automatically entered into forms without ever using the keyboard or clipboard, thereby reducing the possibility that private data is being recorded. However someone with physical access to the machine may still be able to install software that is able to intercept this information elsewhere in the operating system or while in transit on the network. (Transport Layer Security prevents the interception of data in transit by network sniffers and proxy tools.)
Alternative keyboard layouts
Most keylogging hardware/software assumes that a person is using the standard QWERTY keyboard layout, so by using a layout such as Dvorak, frequency analysis is required to determine the mapping of captured keystrokes. For additional security, custom keyboard layouts can be created using tools like the Microsoft Keyboard Layout Creator.
One-time passwords (OTP)
Using one-time passwords is completely keylogger-safe because the recorded password is always invalidated as soon as it's used. This solution is useful if you are often using public computers where you can't verify what is running on them. One-time passwords also prevent replay attacks where an attacker uses the old information to impersonate. One example is online banking where one-time passwords are implemented to protect accounts from keylogging attacks as well as replay attacks.
Smart cards
Because of the integrated circuit of smart cards, the cards themselves are not affected by keylogger and other logging attempts. A smart card can process the information and return back a unique challenge every time you login. The information cannot usually be used to login again. However smartcard readers and their associated keypads for PIN entry are still vulnerable to key logging.
On-screen keyboards
Program-to-program (non-web) keyboards
It is sometimes said that a third-party (or first party) on-screen keyboard program is a good way to combat keyloggers, as it only requires clicks of the mouse. However, this is not always true.
Most on screen keyboards (such as the onscreen keyboard that comes with Microsoft Windows XP) send keyboard event messages to the external target program to type text. Every software keylogger can log these typed characters sent from one program to another. Additionally, some programs also record or take snapshots of what is displayed on the screen (periodically, and/or upon each mouse click).
However, there are some on-screen keyboard programs that do offer some protection, using other techniques described in this article (such as dragging and dropping the password from the on-screen keyboard to the target program).
Web-based keyboards
Web-based on-screen keyboards (written in JavaScript, etc.) may provide some degree of protection. At least some commercial keylogging programs do not record typing on a web-based virtual keyboard. (Screenshot recorders are a concern whenever entire passwords are displayed; fast recorders are generally required to capture a sequence of virtual key presses.)
Notably, the game MapleStory uses, in addition to a standard alphanumeric password, a 4-digit PIN code secured by both on-screen keyboard entry and a randomly changing button pattern; there is no real way to get the latter information without logging the screen and mouse movements; another MMORPG called RuneScape makes a similar system available for players to protect their in-game bank accounts.
Many banks uses the web-based screen keyboard to prevent key logging. HSBC is one of them.
Anti-keylogging software
Keylogger detection software is also available. Some of this type of software use "signatures" from a list of all known keyloggers. The PC's legitimate users can then periodically run a scan from this list, and the software looks for the items from the list on the hard-drive. One drawback of this approach is that it only protects from keyloggers on the signature-based list, with the PC remaining vulnerable to other keyloggers.
Other detection software doesn't use a signature list, but instead analyzes the working methods of many modules in the PC, allowing it to block the work of many different types of keylogger. One drawback of this approach is that it can also block legitimate, non-keylogging software. Some heuristics-based anti-keyloggers have the option to unblock known good software, but this can cause difficulties for inexperienced users.
Speech recognition
Similar to on-screen keyboards, speech-to-text conversion software can also be used against keyloggers, since there are no typing or mouse movements involved. The weakest point of using voice-recognition software may be how the software sends the recognized text to target software after the recognition took place.
Handwriting recognition and mouse gestures
Also, many PDAs and lately Tablet PCs can already convert pen (also called stylus) movements on their touchscreens to computer understandable text successfully. Mouse gestures utilize this principle by using mouse movements instead of a stylus. Mouse gesture programs convert these strokes to user-definable actions, among others typing text. Similarly, graphics tablets and light pens can be used to input these gestures, however, these are getting used less commonly everyday.
The same potential weakness of speech recognition applies to this technique as well.
Macro expanders/recorders
With the help of many Freeware/Shareware programs, a seemingly meaningless text can be expanded to a meaningful text and most of the time context-sensitively, e.g. "we" can be expanded "en.Wikipedia.org" when a browser window has the focus. The biggest weakness of this technique is that these programs send their keystrokes directly to the target program. However, this can be overcome by using the 'alternating' technique described below, i.e. sending mouse clicks to non-responsive areas of the target program, sending meaningless keys, sending another mouse click to target area (e.g. password field) and switching back and forth.
Window transparency
Using many readily available utilities, the target window could be made temporarily transparent, in order to hinder screen-capturing by advanced keyloggers.[citation needed] Although not a fool-proof technique against keyloggers on its own, this could be used in combination with other techniques.
Non-technological methods
Some keyloggers can be fooled by alternating between typing the login credentials and typing characters somewhere else in the focus window. Similarly, a user can move their cursor using the mouse during typing, causing the logged keystrokes to be in the wrong order e.g. by typing a password beginning with the last letter and then using the mouse to move the cursor for each subsequent letter. Lastly, someone can also use context menus to remove, copy, cut and paste parts of the typed text without using the keyboard.
Another very similar technique utilizes the fact that any selected text portion is replaced by the next key typed. E.g. if the password is "secret", one could type "s", then some dummy keys "asdfsd". Then these dummies could be selected with mouse, and next character from the password "e" is typed, which replaces the dummies "asdfsd".
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Branching (software)
Branching, in revision control and software configuration management, is the duplication of an object under revision control (such as a source code file, or a directory tree) so that modifications can happen in parallel along both branches.
Branches are also known as trees, streams or codelines. The originating branch is sometimes called the parent branch, the upstream branch (or simply upstream - especially if the branches are maintained by different organisations or individuals), or the backing stream. Child branches are branches that have a parent; a branch without a parent is referred to as the trunk or the mainline.
In some distributed revision control systems, such as Darcs, there is no distinction made between repositories and branches - so in these systems, fetching a copy of a repository is equivalent to branching.
Branching also generally implies the ability to later merge or integrate changes back onto the parent branch. Often the changes are merged back to the trunk, even if this is not the parent branch. A branch not intended to be merged (e.g. because it has been relicensed under an incompatible license by a third party, or it attempts to serve a different purpose) is usually called a fork.
Branches are created for various reasons. These are covered in depth in the paper "Streamed Lines: Branching Patterns for Parallel Software Development" by Brad Appleton, Stephen Berczuk, Ralph Cabrera, and Robert Orenstein.
Development branch
A development branch or development tree of a piece of software is a version that is under development, and has not yet been officially released. In the open source community, the notion of release is typically metaphorical, since anyone can usually check out any desired version, whether it be in the development branch or not. Often, the version that will eventually become the next major version is called the development branch. However, there is often more than one subsequent version of the software under development at a given time.
Some revision control systems have specific jargon for the main development branch - for example, in CVS, it is called the "MAIN". A more generic term is "mainline".
Shadow
In cvc, an open source package building system (incorporating a simple revision control system for packages) produced by rPath, a shadow is a type of branch which is designed to "shadow" changes made in the upstream branch, to make it easier to maintain small changes
Branches are also known as trees, streams or codelines. The originating branch is sometimes called the parent branch, the upstream branch (or simply upstream - especially if the branches are maintained by different organisations or individuals), or the backing stream. Child branches are branches that have a parent; a branch without a parent is referred to as the trunk or the mainline.
In some distributed revision control systems, such as Darcs, there is no distinction made between repositories and branches - so in these systems, fetching a copy of a repository is equivalent to branching.
Branching also generally implies the ability to later merge or integrate changes back onto the parent branch. Often the changes are merged back to the trunk, even if this is not the parent branch. A branch not intended to be merged (e.g. because it has been relicensed under an incompatible license by a third party, or it attempts to serve a different purpose) is usually called a fork.
Branches are created for various reasons. These are covered in depth in the paper "Streamed Lines: Branching Patterns for Parallel Software Development" by Brad Appleton, Stephen Berczuk, Ralph Cabrera, and Robert Orenstein.
Development branch
A development branch or development tree of a piece of software is a version that is under development, and has not yet been officially released. In the open source community, the notion of release is typically metaphorical, since anyone can usually check out any desired version, whether it be in the development branch or not. Often, the version that will eventually become the next major version is called the development branch. However, there is often more than one subsequent version of the software under development at a given time.
Some revision control systems have specific jargon for the main development branch - for example, in CVS, it is called the "MAIN". A more generic term is "mainline".
Shadow
In cvc, an open source package building system (incorporating a simple revision control system for packages) produced by rPath, a shadow is a type of branch which is designed to "shadow" changes made in the upstream branch, to make it easier to maintain small changes
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