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From Wikipedia, the free encyclopedia
Original author(s)mobman
Preview release
2.3 / 2010
Written inDelphi
Operating systemMicrosoft Windows
TypeTrojan horse (computing)

Sub7, or SubSeven or Sub7Server, is a Trojan horse program originally released in February 1999.[1][2] Its name was derived by spelling NetBus backwards ("suBteN") and swapping "ten" with "seven". As of June 2021, the development of Sub7 is being continued.[3]

Because its typical use is to allow undetected and unauthorized access, Sub7 is usually described as a trojan horse by security experts.[4][2][5][6][7][8] Starting with version 2.1 (1999) it could be controlled via IRC. As one security book phrased it: "This set the stage for all malicious botnets to come."[6] Additionally Sub7 has some features deemed of little use in legitimate remote administration like keystroke logging.[6]

Sub7 worked on the Windows 9x and on the Windows NT family of operating systems, up to and including Windows 8.1.[7]


SubSeven was developed by mobman, a computer programmer originally from Craiova, Romania. [9]

In 2006 (sub7legends.net) re-opened with hundreds of thousands of users, and has kept Sub7 alive with clean downloads and support and new software releases.

No development had occurred for several years until version 2.3 in 2010. This release was based on the genuine SubSeven 2.2 and 2.1.3 source code, which mobman himself shared to his close friends, "Read101" and "fc" and were responsible for this update. Unfortunately, the reborn did not capture the public's attention as anticipated. This lack of interest was primarily due to "fc", who was more interested in monetizing the new version than enhancing its quality.[10]

SubSeven 2.3, released on March 9, 2010, was revamped to work on all 32-bit and 64-bit versions of Windows and includes TCP Tunnel and Password Recovery for browsers, instant messengers and email clients. It was very buggy. The website that claimed to do this is no longer active.

In June 2021, Jean-Pierre Lesueur (DarkCoderSc) released from scratch a complete remake of SubSeven version 2.2. This version maintained a similar look and feel to the original. Since then, development has ceased, and the source code has been made available to the public.[11]

In October 2023, "IllWill", a former member of the Sub7 Crew from the 1990s and early 2000s, delivered a talk at BSides CT 2023.[12] This presentation delved into the story behind mobman, revealing several unknown facts about the mysterious developer. The talk concluded with IllWill releasing the official and genuine source code of SubSeven 2.1.2/3 in his Gitlab.[13] This release was made possible by mobman's direct contribution and with his blessing.

As of now, no other versions of SubSeven have been officially released, apart from version 2.1.2/3 by IllWill. The SubSeven 2.2 version remains exclusively in the possession of mobman, Read101, fc, and DarkCoderSc.

Architecture and features[edit]

Like other remote admin programs, Sub7 is distributed with a server and a client. The server is the program that the host must run in order to have their machines controlled remotely, and the client is the program with a GUI that the user runs on their own machine to control the server/host PC. Computer security expert Steve Gibson once said that with these features, Sub7 allows a hacker to take "virtually complete control" over a computer. Sub7 is so invasive, he said, that anyone with it on their computer "might as well have the hacker standing right next to them" while using their computer.[14]

Sub7 has more features than Netbus (webcam capture, multiple port redirect, user-friendly registry editor, chat and more).

According to a security analysis,[15] Sub7's server-side (target computer) features include:

  • recording:
    • sound files from a microphone attached to the machine
    • images from an attached video camera
    • screen shots of the computer
  • retrieving a listing of recorded and cached passwords
  • taking over an ICQ account used on the target machine (back then the most popular messaging service); added in version 2.1. This included the ability to disable the local use of the account and read the chat history
  • features which were presumably intended to be used for prank or irritating purposes including:
    • changing desktop colors
    • opening and closing the optical drive
    • swapping the mouse buttons
    • turning the monitor off/on
    • "text2speech" voice synthesizer which allowed the remote controller to have the computer "talk" to its user
  • penetration testing features, including a port scanner and a port redirector

On the client-side the software had an "address book" that allowed the controller to know when the target computers are online. Additionally the server program could be customized before being delivered by a so-called server editor (an idea borrowed from Back Orifice 2000). Customizations possible with the Sub7 server editor included changing the port addresses, displaying a customized message upon installation that could be used for example "to deceive the victim and mask the true intent of the program".[15] The Sub7 server could also be configured to notify the controller of IP address changes of the host machine by email, ICQ or IRC.[16]

Connections to Sub7 servers can be password protected with a chosen password.[16] A deeper reverse engineering analysis revealed however that "SubSeven's author has secretly included a hardcoded master password for all of his Trojans! The Trojan itself has been Trojaned".[8] For Version 1.9 the master password is predatox and 14438136782715101980 for versions 2.1 through 2.2b. The Master Password for SubSeven DEFCON8 2.1 Backdoor is acidphreak.[17]

Uses and incidents[edit]

SubSeven has been used to gain unauthorized access to computers. While it can be used for making mischief (such as making sound files play out of nowhere, change screen colors, etc.), it can also read keystrokes that occurred since the last boot—a capability that can be used to steal passwords and credit card numbers.[18]

In 2003, a hacker began distributing a Spanish-language email purporting to be from security firm Symantec that was used to trick recipients into downloading Sub7.[19]

Although Sub7 is not itself a worm (has no built-in self-propagation features) it has been leveraged by some worms such as W32/Leaves (2001).[5][20]

Some versions of Sub7 include code from Hard Drive Killer Pro to format the hard drive; this code will only run if it matches the ICQ number of "7889118" (mobman's rival trojan author.)[21]

See also[edit]


  1. ^ "Sub7 Legacy". www.sub7crew.org. Retrieved 2021-06-19.
  2. ^ a b John R. Vacca (2013). Network and System Security (2nd ed.). Elsevier. p. 63. ISBN 978-0-12-416695-0.
  3. ^ "Sub7 Legacy". www.sub7crew.org. Retrieved 2021-06-19.
  4. ^ Christopher A. Crayton (2003). Security+ Exam Guide. Cengage Learning. p. 340. ISBN 1-58450-251-7.
  5. ^ a b Mohssen Mohammed; Al-Sakib Khan Pathan (July 2013). Automatic Defense Against Zero-day Polymorphic Worms in Communication Networks. CRC Press. p. 105. ISBN 978-1-4822-1905-0.
  6. ^ a b c Craig Schiller; James R. Binkley (2011). Botnets: The Killer Web Applications. Syngress. p. 8. ISBN 978-0-08-050023-2.
  7. ^ a b Diane Barrett; Todd King (2005). Computer Networking Illuminated. Jones & Bartlett Learning. pp. 521–. ISBN 978-0-7637-2676-8.
  8. ^ a b Cyrus Peikari; Anton Chuvakin (2004). Security Warrior. O'Reilly Media. p. 31. ISBN 978-0-596-55239-8.
  9. ^ "A Malware retrospective: SubSeven". medium.com. Retrieved 2024-02-05.
  10. ^ "A Malware retrospective: SubSeven". medium.com. Retrieved 2024-02-05.
  11. ^ "Sub7 Legacy". www.github.com. Retrieved 2021-06-19.
  12. ^ "BSides CT 2023 - illwill: FINDING MOBMAN". www.youtube.com. Retrieved 2023-10-07.
  13. ^ "Sub7". www.gitlab.com. Retrieved 2023-10-07.
  14. ^ Gibson, Steve. The strange tale of the denial of service attacks on grc.com. 2002-03-05.
  15. ^ a b Crapanzano, Jamie (2003), "Deconstructing SubSeven, the Trojan Horse of Choice., SANS Institute Information Security Reading
  16. ^ a b Eric Cole (2002). Hackers Beware. Sams Publishing. p. 569. ISBN 978-0-7357-1009-2.
  17. ^ SANS, A Risk to Your Internet Security Chapter Name: "The Inner Workings of Sub7" on page 14 notes several master passwords used.
  18. ^ Sub7 analysis from Sophos
  19. ^ "Symantec report on Sub7". Symantec.com. Archived from the original on November 10, 2006. Retrieved 2012-08-28.
  20. ^ "The CERT Division | Software Engineering Institute".
  21. ^ admin (2018-12-14). "Who is the real mobman?". illmob. Retrieved 2020-07-15.

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