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AUSCERT External Security Bulletin Redistribution
ESB-2001.115 -- Internet Security Systems Security Alert
A New Version of the SubSeven Backdoor
13 March 2001
AusCERT Security Bulletin Summary
Operating System: Microsoft Windows
Impact: Administrator Compromise
Access Required: Remote
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Internet Security Systems Security Alert
March 12, 2001
A New Version of the SubSeven Backdoor
Internet Security Systems (ISS) X-Force is aware of a new version of the
SubSeven backdoor. This new version, 2.2, has been updated with features
that make it easier for a malicious user to access your computer system
without your knowledge or consent. An attacker can use this backdoor as a
remote control and carry out activities as if he or she were a local user.
SubSeven is a powerful backdoor program, and is the most popular backdoor
used against Windows systems. SubSeven allows an attacker to perform actions
such as shut down or restart a computer, retrieve most saved and cached
passwords, modify the system registry, and upload, download, and delete
files from a system. Due to the potential for damage, SubSeven should be
removed immediately if present on a network.
New Functionality Included in SubSeven 2.2:
SOCKS4/SOCKS5 Proxy Support:
Proxies are intermediaries between two systems, such as a malicious user's
computer and their intended target. Web sites maintain lists of 'open'
proxies, which are known by attackers and traded among them so proxies can
be as starting points. These proxies function to add another location, or
hop, between the user's machine and their target, thereby obscuring the true
location of the attacker's computer.
SubSeven now includes packet sniffing capabilities via a GUI (Graphical User
Interface). The GUI makes the packet sniffer easily accessible and simple
to use. The packet sniffer can be configured to collect network traffic,
save this information into a log, and relay these logs. This information
can be useful for a hacker wishing to mount further attacks on the target
network, as well as obtain more information about the target individual or
Ability to Listen on a Random Port:
The SubSeven server can be configured to listen on a random port each time
it is started. This makes the program harder to detect than previous
versions. SubSeven can be configured to notify the hacker of the port
Expanded Notification Capability:
SubSeven has expanded notification capabilities. In addition to IRC
(Internet Relay Chat), Mirabilis ICQ, and email notification, SubSeven can
relay information to web sites using CGI (Common Gateway Interface) scripts
as well as route information to an IP address determined by the operator.
CGI notification was designed and integrated in response to SubSeven's
popularity as a DDoS (Distributed Denial of Service) agent. Lists of
compromised computers are traded for use in DDoS networks. With CGI
notification enabled, attackers can configure SubSeven agents to
automatically post information to a URL using CGI. This allows a list of
SubSeven agents to be easily distributed among those wishing to use them for
Static IP number notification is a new feature that sends customized IP
traffic to an IP address specified during the program's configuration.
Ability to E-mail Keystroke Logs:
SubSeven has been able to log keystrokes in previous versions. In version
2.2, the program has the ability to send logs of entered keystrokes via
email. This can be used to gather information such as user and network
passwords and email this information to be used at a later time. SubSeven
can also send passwords stored on the system (RAS, dialup, etc.) as well as
passwords captured from password dialogues.
Modular Design and SDK:
The architecture of SubSeven 2.2 is modular, with most of the program's
functionality residing in plugin DLL's. There are plans to release an SDK
for creating custom plugins, which (combined with the program's modular
design) will make SubSeven 2.2 harder to detect than previous versions. The
SDK will also provide a means for adding functionality and some
customization the program's features.
Support to detect SubSeven is available for Internet Scanner customers in
X-Press Update v4.6 and for RealSecure customers in X-Press Update v1.1.
Refer to the ISS Alert titled "Widespread incidents of SubSeven DEFCON8 2.1
Backdoor" at <http://xforce.iss.net/alerts/advise65.php> for more
The Common Vulnerabilities and Exposures (CVE) project has assigned the
following names to these issues. These are candidates for inclusion in the
CVE list (<http://cve.mitre.org>), which standardizes names for security
CAN-1999-0660 A hacker utility or Trojan Horse is installed on a system.
CAN-2000-0138 A system has a distributed denial of service (DDOS) attack
master, agent, or zombie installed.
About Internet Security Systems (ISS)
Internet Security Systems (ISS) is a leading global provider of security
management solutions for the Internet. By providing industry-leading
SAFEsuite security software, remote managed security services, and strategic
consulting and education offerings, ISS is a trusted security provider to
its customers, protecting digital assets and ensuring safe and uninterrupted
e-business. ISS' security management solutions protect more than 5,500
customers worldwide including 21 of the 25 largest U.S. commercial banks, 10
of the largest telecommunications companies and over 35 government agencies.
Founded in 1994, ISS is headquartered in Atlanta, GA, with additional
offices throughout North America and international operations in Asia,
Australia, Europe, Latin America and the Middle East. For more information,
visit the Internet Security Systems web site at www.iss.net or call
Copyright (c) 2001 Internet Security Systems, Inc.
Permission is hereby granted for the redistribution of this Alert
electronically. It is not to be edited in any way without express consent of
the X-Force. If you wish to reprint the whole or any part of this Alert in
any other medium excluding electronic medium, please e-mail firstname.lastname@example.org
The information within this paper may change without notice. Use of this
information constitutes acceptance for use in an AS IS condition. There are
NO warranties with regard to this information. In no event shall the author
be liable for any damages whatsoever arising out of or in connection with
the use or spread of this information. Any use of this information is at the
user's own risk.
X-Force PGP Key available at: <http://xforce.iss.net/sensitive.php> as well
as on MIT's PGP key server and PGP.com's key server.
Please send suggestions, updates, and comments to: X-Force
email@example.com <mailto:firstname.lastname@example.org> of Internet Security Systems, Inc.
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