Trojan.Win32.Sasfis_82570ebceb

by malwarelabrobot on September 10th, 2013 in Malware Descriptions.

HEUR:Trojan.Win32.Generic (Kaspersky), Backdoor.IRCBot (VIPRE), Backdoor.Win32.Fynloski!IK (Emsisoft), Trojan.Win32.Sasfis.FD, VirTool.Win32.DelfInject.FD, GenericAutorunWorm.YR (Lavasoft MAS)
Behaviour: Trojan, Backdoor, Worm, VirTool, WormAutorun, IRCBot


The description has been automatically generated by Lavasoft Malware Analysis System and it may contain incomplete or inaccurate information.

Summary
Technical Details
Removal Recommendations

MD5: 82570ebcebe0aaa2ceb791fe6a7f565c
SHA1: 8f5b991bce5cd05e5dc4485124f10210c5d7cd0a
SHA256: 3b850fa2ba34f1ce048a418e2df05156d7120dc640712da12a60ff266e084639
SSDeep: 6144:UBudLvxoeilwc4ybTNaaaOX99xERXmJqYfjdefmOEY6Oar0rjolELy0gJdF:UGfkwc4ybTNaaaqvE9mJpfjkfRlFar0S
Size: 333872 bytes
File type: EXE
Platform: WIN32
Entropy: Packed
PEID: UPolyXv05_v6
Company: InstallManager
Created at: 2013-03-22 12:17:21


Summary:

Trojan. A program that appears to do one thing but actually does another (a.k.a. Trojan Horse).

Payload

Behaviour Description
WormAutorun A worm can spread via removable drives. It writes its executable and creates "autorun.inf" scripts on all removable drives. The autorun script will execute the Trojan's file once a user opens a drive's folder in Windows Explorer.
IRCBot A bot can communicate with command and control servers via IRC channel.


Process activity

The Trojan creates the following process(es):

winlog.exe:1712
82570ebcebe0aaa2ceb791fe6a7f565c.exe:1116

The Trojan injects its code into the following process(es):

winlog.exe:1680

File activity

The process winlog.exe:1680 makes changes in a file system.
The Trojan deletes the following file(s):

%Documents and Settings%\%current user%\Application Data\Microsoft\winlog.exe (0 bytes)

The process 82570ebcebe0aaa2ceb791fe6a7f565c.exe:1116 makes changes in a file system.
The Trojan creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\Microsoft\winlog.exe (2105 bytes)

Registry activity

The process winlog.exe:1680 makes changes in a system registry.
The Trojan creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "4F 70 2F E1 AC 4F 1A 8E 66 EE A1 5E 13 00 2A 33"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

To automatically run itself each time Windows is booted, the Trojan adds the following link to its file to the system registry autorun key:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"winlog.exe" = "%Documents and Settings%\%current user%\Application Data\Microsoft\winlog.exe"

The process 82570ebcebe0aaa2ceb791fe6a7f565c.exe:1116 makes changes in a system registry.
The Trojan creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D1 01 A8 5A D7 F3 C6 F0 CD D5 C0 8B 1D 73 E4 CB"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd73-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cookies" = "%Documents and Settings%\%current user%\Cookies"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Common Documents" = "%Documents and Settings%\All Users\Documents"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Desktop" = "%Documents and Settings%\%current user%\Desktop"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd72-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{b98117e8-75ca-11e2-81b2-000c293708fb}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Common Desktop" = "%Documents and Settings%\All Users\Desktop"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Personal" = "%Documents and Settings%\%current user%\My Documents"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Application Data\Microsoft]
"winlog.exe" = "winlog"

The Trojan modifies IE settings for security zones to map all urls to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"IntranetName" = "1"

The Trojan modifies IE settings for security zones to map all local web-nodes with no dots which do not refer to any zone to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"UNCAsIntranet" = "1"

The Trojan modifies IE settings for security zones to map all web-nodes that bypassing proxy to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"ProxyBypass" = "1"

Network activity (URLs)

No activity has been detected.

Rootkit activity

No anomalies have been detected.

Propagation

A worm can spread via removable drives. It writes its executable and creates "autorun.inf" scripts on all removable drives. The autorun script will execute the Trojan's file once a user opens a drive's folder in Windows Explorer.


Remove it with Ad-Aware

  1. Click (here) to download and install Ad-Aware Free Antivirus.
  2. Update the definition files.
  3. Run a full scan of your computer.


Manual removal*

  1. Terminate malicious process(es) (How to End a Process With the Task Manager):

    winlog.exe:1712
    82570ebcebe0aaa2ceb791fe6a7f565c.exe:1116

  2. Delete the original Trojan file.
  3. Delete or disinfect the following files created/modified by the Trojan:

    %Documents and Settings%\%current user%\Application Data\Microsoft\winlog.exe (2105 bytes)

  4. Delete the following value(s) in the autorun key (How to Work with System Registry):

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "winlog.exe" = "%Documents and Settings%\%current user%\Application Data\Microsoft\winlog.exe"

  5. Find and delete all copies of the worm's file together with "autorun.inf" scripts on removable drives.
  6. Reboot the computer.

*Manual removal may cause unexpected system behaviour and should be performed at your own risk.