BKDR64_OLMASCO.A

February 19, 2013
 Analysis by: Michael Cabel
 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size:

39,936 bytes

File Type:

SYS

Memory Resident:

Yes

Initial Samples Received Date:

16 Feb 2013

Arrival Details

This backdoor 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 backdoor drops a copy of itself in the following folders using different file names:

  • %System%\drivers

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It injects itself into the following processes running in the affected system's memory:

  • svchost.exe
  • explorer.exe
  • services.exe

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\REGISTRY\MACHINE\
SYSTEM\CurrentControlSet\Services\
{Malware Filename}

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.732.02

FIRST VSAPI PATTERN DATE:

16 Feb 2013

VSAPI OPR PATTERN File:

9.733.00

VSAPI OPR PATTERN Date:

17 Feb 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product and note files detected as BKDR64_OLMASCO.A

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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\REGISTRY\MACHINE\SYSTEM\CurrentControlSet\Services
    • {Malware Filename}

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR64_OLMASCO.A. 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.


Did this description help? Tell us how we did.