Select local site

| Japanese | Simplified Chinese | Traditional Chinese (Hong Kong) | Traditional Chinese (Taiwan)

F-Secure Trojan Information Pages: Agent.AGW
[Summary] | [Disinfection] | [Detailed Description] | [Detection]

Name : Agent.AGW
Alias:W32/Sdbot.worm.gen.ca, W32/Oscarbot.KX.worm, WORM_SDBOT.AHP, Backdoor.Win32.Agent.agw
Size:1,012,736 bytes
Type:Backdoor
Category:Trojan
Platform:Win32
Date of Discovery:September 04, 2006
Radar

Summary
Agent.AGW is a backdoor program that allows contol over a victim's computers remotely by sending specific commands via IRC channels. This backdoor can also steal data, spread to a local network, and to computers vulnerable to exploits.
Back to the Top

Disinfection

Automatic Disinfection

Usually standalone malware (backdoors, worms, trojans, etc.) is automatically removed by F-Secure Anti-Virus (FSAV) starting from version 5.40. Malware files get automatically renamed by FSAV, so they can not be started any more. In some rare cases, when automatic disinfection is not possible, a user can select disinfection action by him/herself to make FSAV rename or delete an infected file. In some special cases it is recommended to use specific disinfection tools provided by F-Secure. They can be downloaded from our ftp site:

ftp://ftp.f-secure.com/anti-virus/tools/

F-Secure Anti-Virus can be purchased from our webshop or from our authorised distributors. A trial version F-Secure Anti-Virus, limited to 30 days, can be downloaded from our website:

http://www.f-secure.com/download-purchase/

All the latest versions of FSAV can download anti-virus database updates automatically. However, these updates can be also downloaded and installed manually from our web or ftp sites:

http://www.f-secure.com/download-purchase/updates.shtml


Manual Disinfection

To manually disinfect standalone malware (backdoors, worms, trojans, etc.) it's usually enough to delete all infected files from a computer and to restart it. Active malware files are usually locked by operating system so different disinfection approaches are required for different operating systems.
Please note that manual disinfection is a risky process, so it is recommended only for advanced users.

If Windows 95, 98 and ME operating system is used, it is recommended to restart a computer from a bootable system diskette and to delete an infected file from command prompt. For example if a malicious file named ABC.EXE is located in Windows folder, it is usually enough to type the following command at command prompt:

DEL C:\WINDOWS\ABC.EXE

and to press Enter. After that an infected file will be gone. If Windows NT, 2000 or XP is used, a malicious file has to be renamed with a different extension (for example .VIR) and then a system has to be restarted. After restart a renamed malicious file will no longer be active and it can be easily deleted manually.


Malware Disinfection Tools

F-Secure provides disinfection tools for certain malware. These tools can be downloaded from this webpage:

http://www.f-secure.com/download-purchase/tools.shtml

ftp://ftp.f-secure.com/anti-virus/tools/


Windows System Restore Issues

If Windows ME or XP is used, it is recommended to disable System Restore feature of these operating systems to prevent a computer from re-infection by an already removed malware. The fact is that System Restore feature of these operating systems might save an infected file into the special folder and copy it back to a hard drive it every time it's been renamed or deleted by F-Secure Anti-Virus or by a user. Instructions on how to disable System Restore feature are here:

Windows ME:
http://www.f-secure.com/v-descs/sfc_dis.shtml

Windows XP:
http://www.f-secure.com/v-descs/sfc_dis1.shtml

It is recommended to re-enable System Restore after disinfection in order to restore stable system configuration in the future, if any crash or incompatibility issue occurs.


Failed Disinfection

In some cases F-Secure Anti-Virus might not disinfect a system automatically. In this case please visit our Support pages:

http://support.f-secure.com/enu/home/virusproblem/howtoclean/
Back to the Top

Detailed Description
Agent.AGW is a backdoor program that allows control over a victim's computers remotely by sending specific commands via IRC channels. This backdoor can also steal data, spread to a local network, and to computers vulnerable to exploits.


Upon execution, it drops the following files:

  • %WinDir%\lsass.exe
    - a copy of itself.
  • %SysDir%\rdriv.sys
    - a trojan rootkit used to hide its presence on the machine. This is now detected as Rootkit.Win32.Agent.p.

Note: %WinDir%" represents the Windows root directory and "%SysDir%" represents the Windows System directory.


It installs itself as a service by creating the following registry keys:

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lsass]
  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\rdriv]


It installs itself as a service by creating the following registry keys:

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lsass]


It creates the following registry entries to lower the system's security settings:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center]
    UpdatesDisableNotify = "dword:00000000"
    AntiVirusDisableNotify = "dword:00000000"
    FirewallDisableNotify = "dword:0000000"
    AntiVirusOverride = "dword:00000000"
    FirewallOverride = "dword:00000000"
  • [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate]
    DoNotAllowXPSP2 = dword:00000001
  • [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile]
    EnableFirewall = "dword:00000000"
  • [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile]
    EnableFirewall = "dword:00000000"


It creates the following registry entries to disable Administrative Shares in NT4.0 Server and Workstation:

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters]
    AutoShareWks = "dword:00000000"
    AutoShareServer = "dword:00000000"
  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanworkstation\parameters]
    AutoShareWks = "dword:00000000"
    AutoShareServer = "dword:00000000"


Agent.AGW also modifies the following registry entries to disable and restrict anonymous access and DCOM network binding:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole]
    EnableDCOM = "N"

Note: the default value is EnableDCOM = "Y".

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa]
    restrictanonymous = "dword:00000001"

Note: The default value for restrictanonymous is user dependent.


Agent.AGW also disables automatic update of Service Pack 2 in Windows XP by changing the following registry entry:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate]
    DoNotAllowXPSP2 = "1"

Note: The default value for DoNotAllowXPSP2 = "0".


It modifies the following regsitry entry to shorten the waiting time for services to stop after service notification of system Shutdown:

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control]
    WaitToKillServiceTimeout= "7000"

Note: This is equivalent to 7 seconds. The default value is WaitToKillServiceTimeout= "20000", which is equivalent to 20 seconds.


It also disables the Messenger, Remote Registry, Security Center, and Telnet services respectively by modifiying the following regsitry entries:

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Messenger]
    Start = "dword:00000004"

Note: Default value is Start = "dword:00000002".

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RemoteRegistry]
    Start = "dword:00000004"

Note: Default value for Start = "dword:00000002".

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\wscsvc]
    Start = "dword:00000004"

Note: Default value is Start = "dword:00000002".

  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TlntSvr]
    Start = "dword:00000004"

Note: Default value is Start = "dword:00000003".


Agent.AGW attempts to connect to the following IRC server:

  • bla.girlsontheblock.com


It attempts to join the following IRC channels:

  • #na-e
  • #na-s


Once successfully connected, a hacker can send commands to the bots on the IRC channel to control the infected computer. It has the ability to do the following:

  • Display System Information
  • Download and Upload a File
  • List current processes
  • Scan for Files
  • Execute a file
  • Perform denial of service attack
  • Steal user information and log keyboard and mouse events
  • Send copies using different IM applications
  • Visit websites
  • Enumerate remote shares
  • Scan and exploit computers vulnerable to exploits


When spreading, the bot can exploit the following vulnerabilities:

  • Vulnerability in Plug and Play Could Allow Remote Code Execution and Elevation of Privilege (MS05-039) port 445
  • Vulnerability in Server Service Could Allow Remote Code Execution (MS06-040) port 139


It uses the following user accounts:

  • administrator
  • admin

- to connect to the target machine's hidden shares:

  • Admin$
  • ipc$

- by using the following list of weak passwords:

  • 12345
  • 123456
  • 654321
  • admin
  • asdfgh
  • server


It also tries to steal usernames and passwords from the following known applications:

  • MSN Hotmail
  • Outlook Express
  • PayPal
Back to the Top

Detection

F-Secure Anti-Virus detects this malware with the following updates:

[FSAV_Database_Version]

Version = 2006-09-05_02.
Back to the Top



F-Secure Corporation

Last Modified: September 06, 2006