TROJ_CLEAMAN.BK

October 09, 2012
 Analysis by: Kathleen Notario
 ALIASES:

Trojan:Win32/Cleaman.G (Microsoft); Trojan.Win32.Menti.mdoc (Kaspersky); 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 It hooks APIs for its rootkit functionalities.

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 also has rootkit capabilities, which enables it to hide its processes and files from the user.

It does not have any downloading capability.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size:

87,544 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 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 files:

  • %User Profile%\Application Data\dplayx.dll - also detected as TROJ_CLEAMAN.BK

(Note: %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.)

It drops the following copies of itself into the affected system:

  • %User Profile%\Application Data\dplaysvr.exe

(Note: %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.)

It drops the following non-malicious file:

  • %User Temp%\ayne6924.log

(Note: %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:

  • FxCUnzSQclbQl3

Autostart Technique

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

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

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Rootkit Capabilities

This Trojan also has rootkit capabilities, which enables it to hide its processes and files from the user.

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 hooks the following APIs for its rootkit functionalities:

  • FindFirstFileA
  • FindNextFileA
  • FindFirstFileW
  • FindNextFileW
  • NtEnumerateValueKey
  • NtResumeThread
  • NtQuerySystemInformation
  • LdrLoadDll
  • connect

It hides all files with the following filenames:

  • dplaysvr.exe
  • dplayx.dll

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.812.03

FIRST VSAPI PATTERN DATE:

02 Mar 2012

VSAPI OPR PATTERN File:

8.813.00

VSAPI OPR PATTERN Date:

03 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 delete files detected as TROJ_CLEAMAN.BK using either the Startup Disk or Recovery Console

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • dplaysvr = "%User Profile%\Application Data\dplaysvr.exe"

Step 4

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.  
  • %User Temp%\ayne6924.log

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_CLEAMAN.BK. 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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