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The Internet threat alert status is currently normal. At present, no major epidemics or other serious incidents have been recorded by Kaspersky Lab’s monitoring service. Internet threat level: 1

Backdoor.Win32.AckCmd

Detected Jul 27 2006 08:06 GMT
Released Jan 18 2008 14:08 GMT
Published Jul 27 2006 08:06 GMT

Technical Details
Payload
Removal instructions

Technical Details

This Troajn program can be used for remote administration of the victim machine. It has both a client and a server component.

The server component is written in Microsoft Visual C++. It is 28672 bytes in size, and is not packed in any way. The client component is also written in Microsoft Visual C++, and it 32768 bytes in size. It is not packed in any way.


Payload

The remote malicious user launches the client component on his/ her machine. This makes it possible to send commands to the server component which is installed on the victim machine. The malicious user has to give the address of the victim machine.

The program contains the following strings:

AckCmd 1.1 - The Ack Command Prompt for Windows 2000
- (c) 2000, **** Vidstrom, ****.vidstrom@****curity.nu
- For instructions see http://****curity.nu/toolbox/ackcmd/

The server component makes it possible for the remote malicious user to open the command line on the victim machine and execute commands via the command line on the victim machine.

The interesting feature about this backdoor is that it only uses ACK packets. This means that a standard connection is not established; rather, data will be transmitted directly using ACK packets. This makes it possible for the Trojan to bypass some firewalls.

The backdoor does not have any replication routine.


Removal instructions

  1. Use Task Manager to terminate the Trojan process.
  2. Delete the original backdoor file (its location on the victim machine will depend on how the program originally penetrated the victim machine).
  3. Update your antivirus databases, and perform a full scan of the computer (download a trial version of Kaspersky Anti-Virus).

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Backdoor

Backdoors are designed to give malicious users remote control over an infected computer. In terms of functionality, Backdoors are similar to many administration systems designed and distributed by software developers.

These types of malicious programs make it possible to do anything the author wants on the infected computer: send and receive files, launch files or delete them, display messages, delete data, reboot the computer, etc.

The programs in this category are often used in order to unite a group of victim computers and form a botnet or zombie network. This gives malicious users centralized control over an army of infected computers which can then be used for criminal purposes.

There is also a group of Backdoors which are capable of spreading via networks and infecting other computers as Net-Worms do. The difference is that such Backdoors do not spread automatically (as Net-Worms do), but only upon a special “command” from the malicious user that controls them.


Aliases

Backdoor.Win32.AckCmd (Kaspersky Lab) is also known as:

  • Backdoor.AckCmd (Kaspersky Lab)
  • Backdoor.AckCmd.client (Kaspersky Lab)
  • Backdoor.AckCmd.server (Kaspersky Lab)
  • Trojan: BackDoor-IO (McAfee)
  • Troj/AckCmd (Sophos)
  • Troj/Bdoor-FR (Sophos)
  • Trojan.AckCmd.Server (ClamAV)
  • Bck/AckCmd.Ser (Panda)
  • Bck/AckCmd.Cli (Panda)
  • W32/Malware!941e (FPROT)
  • W32/Backdoor.OKR (FPROT)
  • Backdoor:Win32/AckCmd (MS(OneCare))
  • BackDoor.AckCmd.11 (DrWeb)
  • Win32/AckCmd trojan (Nod32)
  • Backdoor.AckCmd (BitDef7)
  • Backdoor.AckCmd!tKZJ5lnz0e0 (VirusBuster)
  • Backdoor.AckCmd!wfJh+3gfPVo (VirusBuster)
  • Win32:Ackcmd [Trj] (AVAST)
  • Win32:VB-AMV [Trj] (AVAST)
  • Backdoor.Win32.AckCmd (Ikarus)
  • Backdoor.AckCmd (AVG)
  • AckCmdS.exe <<< BDS/AckCmd.1 (AVIRA)
  • BDC/AckCmd.2 (AVIRA)
  • BDS/AckCmd.1 (AVIRA)
  • BACKDOOR.Trojan (NAV)
  • Trojan Horse (NAV)
  • NseCheckFile2() returned 0x00010018 (Norman)
  • BackDoor-IO (NAI)
  • BKDR_ACKCMD.A (PCCIL)
  • Trojan.AckCmd (Rising)
  • Backdoor.Win32.Small.xre (Rising)
  • Backdoor.Win32.AckCmd [AVP] (FSecure)
  • BKDR_ACKCMD.A (TrendMicro)
  • Trojan.Win32.Generic!BT (Sunbelt)
  • Backdoor.AckCmd!wfJh+3gfPVo (VirusBusterBeta)
  • Backdoor.AckCmd!tKZJ5lnz0e0 (VirusBusterBeta)