PGPCoder

Last updated
Trojan.PGPCoder
Common nameGpcode
Technical name
  • Trojan.PGPCoder,
  • Virus.Win32.Gpcode,
  • TROJ_PGPCODER.[letter] (Trend Micro)
Classification Trojan
Isolation2005-05-20

PGPCoder or GPCode is a trojan that encrypts files on the infected computer and then asks for a ransom in order to release these files, a type of behavior dubbed ransomware or cryptovirology.

Contents

Trojan

Once installed on a computer, the trojan creates two registry keys: one to ensure it is run on every system startup, and the second to monitor the progress of the trojan in the infected computer, counting the number of files that have been analyzed by the malicious code.

Once it has been run, the trojan embarks on its mission, which is to encrypt, using a digital encryption key, all the files it finds on computer drives with extensions corresponding to those listed in its code. These extensions include .doc, .html, .jpg, .xls, .zip, and .rar.

The blackmail is completed with the trojan dropping a text file in each directory, with instructions to the victim of what to do. An email address is supplied through which users are supposed to request for their files to be released after paying a ransom of $100–200 to an e-gold or Liberty Reserve account. [1]

Efforts to combat the trojan

While a few Gpcode variants have been successfully implemented, [2] many variants have flaws that allow users to recover data without paying the ransom fee. The first versions of Gpcode used a custom-written encryption routine that was easily broken. [3] Variant Gpcode.ak writes the encrypted file to a new location, and deletes the unencrypted file, and this allows an undeletion utility to recover some of the files. Once some encrypted+unencrypted pairs have been found, this sometimes gives enough information to decrypt other files. [4] [5] [6] Variant Gpcode.am uses symmetric encryption, which made key recovery very easy. [7] In late November 2010, a new version called Gpcode.ax [8] was reported. It uses stronger encryption (RSA-1024 and AES-256) and physically overwrites the encrypted file, making recovery nearly impossible. [9]

Kaspersky Lab has been able to make contact with the author of the program, and verify that the individual is the real author, but have so far been unable to determine his real world identity. [10]

Related Research Articles

Malware is any software intentionally designed to cause disruption to a computer, server, client, or computer network, leak private information, gain unauthorized access to information or systems, deprive access to information, or which unknowingly interferes with the user's computer security and privacy. Researchers tend to classify malware into one or more sub-types.

<span class="mw-page-title-main">Timeline of computer viruses and worms</span> Computer malware timeline

This timeline of computer viruses and worms presents a chronological timeline of noteworthy computer viruses, computer worms, Trojan horses, similar malware, related research and events.

Ransomware is a type of cryptovirological malware that permanently blocks access to the victim's personal data unless a ransom is paid. While some simple ransomware may lock the system without damaging any files, more advanced malware uses a technique called cryptoviral extortion. It encrypts the victim's files, making them inaccessible, and demands a ransom payment to decrypt them. In a properly implemented cryptoviral extortion attack, recovering the files without the decryption key is an intractable problem, and difficult-to-trace digital currencies such as paysafecard or Bitcoin and other cryptocurrencies are used for the ransoms, making tracing and prosecuting the perpetrators difficult.

<span class="mw-page-title-main">AIDS (Trojan horse)</span> Early example of ransomware

AIDS, also known as Aids Info Disk or PC Cyborg Trojan, is a DOS Trojan horse whose payload mungs and encrypts the names of all directories on drive C:. It was developed by Dr. Joseph Popp (1950-2006), an evolutionary biologist with a doctorate from Harvard. The virus was isolated in 1989.

Encryption software is software that uses cryptography to prevent unauthorized access to digital information. Cryptography is used to protect digital information on computers as well as the digital information that is sent to other computers over the Internet.

OneHalf is a DOS-based polymorphic computer virus discovered in October 1994. It is also known as Slovak Bomber, Freelove or Explosion-II. It infects the master boot record (MBR) of the hard disk, and any files with extensions .COM, .SCR and .EXE. However, it will not infect files that have SCAN, CLEAN, FINDVIRU, GUARD, NOD, VSAFE, MSAV or CHKDSK in the name.

Cryptovirology refers to the study of cryptography use in malware, such as ransomware and asymmetric backdoors. Traditionally, cryptography and its applications are defensive in nature, and provide privacy, authentication, and security to users. Cryptovirology employs a twist on cryptography, showing that it can also be used offensively. It can be used to mount extortion based attacks that cause loss of access to information, loss of confidentiality, and information leakage, tasks which cryptography typically prevents.

In computer security, a wiper is a class of malware intended to erase the hard drive or other static memory of the computer it infects, maliciously deleting data and programs.

The CryptoLocker ransomware attack was a cyberattack using the CryptoLocker ransomware that occurred from 5 September 2013 to late May 2014. The attack utilized a trojan that targeted computers running Microsoft Windows, and was believed to have first been posted to the Internet on 5 September 2013. It propagated via infected email attachments, and via an existing Gameover ZeuS botnet. When activated, the malware encrypted certain types of files stored on local and mounted network drives using RSA public-key cryptography, with the private key stored only on the malware's control servers. The malware then displayed a message which offered to decrypt the data if a payment was made by a stated deadline, and it threatened to delete the private key if the deadline passes. If the deadline was not met, the malware offered to decrypt data via an online service provided by the malware's operators, for a significantly higher price in bitcoin. There was no guarantee that payment would release the encrypted content.

Regin is a sophisticated malware and hacking toolkit used by United States' National Security Agency (NSA) and its British counterpart, the Government Communications Headquarters (GCHQ). It was first publicly revealed by Kaspersky Lab, Symantec, and The Intercept in November 2014. The malware targets specific users of Microsoft Windows-based computers and has been linked to the US intelligence-gathering agency NSA and its British counterpart, the GCHQ. The Intercept provided samples of Regin for download, including malware discovered at a Belgian telecommunications provider, Belgacom. Kaspersky Lab says it first became aware of Regin in spring 2012, but some of the earliest samples date from 2003. Among computers infected worldwide by Regin, 28 percent were in Russia, 24 percent in Saudi Arabia, 9 percent each in Mexico and Ireland, and 5 percent in each of India, Afghanistan, Iran, Belgium, Austria, and Pakistan.

TeslaCrypt was a ransomware trojan. It is now defunct, and its master key was released by the developers.

Linux.Encoder is considered to be the first ransomware Trojan targeting computers running Linux. There are additional variants of this Trojan that target other Unix and Unix-like systems. Discovered on November 5, 2015, by Dr. Web, this malware affected at least tens of Linux users.

<span class="mw-page-title-main">KeRanger</span> MacOS ransomware

KeRanger is a ransomware trojan horse targeting computers running macOS. Discovered on March 4, 2016, by Palo Alto Networks, it affected more than 7,000 Mac users.

TorrentLocker is a ransomware trojan targeting Microsoft Windows. It was first observed in February 2014, with at least five of its major releases made available by December 2014. The malware encrypts the victim's files in a similar manner to CryptoLocker by implementing symmetric block cipher AES where the key is encrypted with an asymmetric cipher.

<span class="mw-page-title-main">Locky</span>

Locky is ransomware malware released in 2016. It is delivered by email with an attached Microsoft Word document that contains malicious macros. When the user opens the document, it appears to be full of gibberish, and includes the phrase "Enable macro if data encoding is incorrect," a social engineering technique. If the user does enable macros, they save and run a binary file that downloads the actual encryption Trojan, which will encrypt all files that match particular extensions. Filenames are converted to a unique 16 letter and number combination. Initially, only the .locky file extension was used for these encrypted files. Subsequently, other file extensions have been used, including .zepto, .odin, .aesir, .thor, and .zzzzz. After encryption, a message instructs them to download the Tor browser and visit a specific criminal-operated Web site for further information.

Trojan.Win32.DNSChanger is a backdoor trojan that redirects users to various malicious websites through the means of altering the DNS settings of a victim's computer. The malware strain was first discovered by Microsoft Malware Protection Center on December 7, 2006 and later detected by McAfee Labs on April 19, 2009.

<span class="mw-page-title-main">Petya (malware family)</span> Family of encrypting ransomware discovered in 2016

Petya is a family of encrypting malware that was first discovered in 2016. The malware targets Microsoft Windows–based systems, infecting the master boot record to execute a payload that encrypts a hard drive's file system table and prevents Windows from booting. It subsequently demands that the user make a payment in Bitcoin in order to regain access to the system.

<span class="mw-page-title-main">Jigsaw (ransomware)</span> Encrypting ransomware created in 2016

Jigsaw is a form of encrypting ransomware malware created in 2016. It was initially titled "BitcoinBlackmailer", but later came to be known as "Jigsaw" due to featuring an image of Billy the Puppet from the Saw film franchise. The malware encrypts computer files and gradually deletes them, demanding payment of a ransom to decrypt the files and halt the deletion.

<span class="mw-page-title-main">Kirk Ransomware</span> Ransomware malware, discovered in 2017

Kirk Ransomware, or Kirk, is malware. It encrypts files on an infected computer and demands payment for decryption in the cryptocurrency Monero. The ransomware was first discovered in 2017, by Avast researcher Jakub Kroustek.

Ryuk is a type of ransomware known for targeting large, public-entity Microsoft Windows cybersystems. It typically encrypts data on an infected system, rendering the data inaccessible until a ransom is paid in untraceable bitcoin. Ryuk is believed to be used by two or more criminal groups, most likely Russian, who target organizations rather than individual consumers.

References

  1. Eran Tromer. "Cryptanalysis of the Gpcode.ak ransomware virus" (PDF). Retrieved 2008-09-30.
  2. "Kaspersky Lab announces the launch of Stop Gpcode, an international initiative against the blackmailer virus". 2008-06-09.
  3. "Blackmailer: the story of Gpcode". Kaspersky Labs. 2006-07-26.
  4. "Utilities which fight Virus.Win32.Gpcode.ak". Kaspersky Lab. 2008-06-25.
  5. "Restoring files attacked by Gpcode.ak". Kaspersky Labs. 2008-06-13. Archived from the original on 2009-07-13. Retrieved 2008-09-30.
  6. "Another way of restoring files after a Gpcode attack". 2008-06-26. Archived from the original on 2013-02-09.
  7. "New Gpcode - mostly hot air". Kaspersky Labs. 2008-08-14. Archived from the original on 2012-09-18.
  8. "GpCode Ransomware 2010 Simple Analysis". Xylibox. 2011-01-30.
  9. "GpCode-like Ransomware Is Back". Kaspersky Labs. 2010-11-29.
  10. "Police 'find' author of notorious virus". TechWorld. 2008-09-30.