TROJ_CRED.B

 Analysis by: Kathleen Notario

 ALIASES:

TrojanDownloader:Win32/Cred.B (Microsoft); Mal/Cleaman-B (Sophos)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

It does not have any backdoor routine.

It does not have any downloading capability.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size:

81,912 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Mar 2012

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System Root%\Documents and Settings\All Users\logonquery.exe
  • %User Profile%\Application Data\playdevice.exe
  • %User Temp%\srvlogon.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • gtr34583409freio

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
logonquery = "%System Root%\Documents and Settings\All Users\logonquery.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
playdevice = "%User Profile%\Application Data\playdevice.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
logonquery = "%System Root%\Documents and Settings\All Users\logonquery.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
playdevice = "%User Profile%\Application Data\playdevice.exe"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\体呆䅗䕒䵜捩潲潳瑦坜湩潤獷䍜牵敲瑮敖獲潩屮畒屮
srvlogon = "%User Temp%\srvlogon.exe"

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Download Routine

This Trojan does not have any downloading capability.

Information Theft

This Trojan does not have any information-stealing capability.

NOTES:

Other Details

It accesses the following URL to notify the malicious user of its installation:

  • http://{BLOCKED}earch.com/adv.php?i=13&rnd={random numbers}

This malware does not have rootkit capabilities.

This malware does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.810.05

FIRST VSAPI PATTERN DATE:

01 Mar 2012

VSAPI OPR PATTERN File:

8.811.00

VSAPI OPR PATTERN Date:

02 Mar 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Identify and terminate files detected as TROJ_CRED.B

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • logonquery = "%System Root%\Documents and Settings\All Users\logonquery.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • playdevice = "%User Profile%\Application Data\playdevice.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • logonquery = "%System Root%\Documents and Settings\All Users\logonquery.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • playdevice = "%User Profile%\Application Data\playdevice.exe"
  • In HKEY_CURRENT_USER\体呆䅗䕒䵜捩潲潳瑦坜湩潤獷䍜牵敲瑮敖獲潩屮畒屮
    • srvlogon = "%User Temp%\srvlogon.exe"

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_CRED.B. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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