RTKT_POPUREB.A

 Analysis by: kathleenno

 ALIASES:

Hacktool.Rootkit (Symantec); VirTool:WinNT/Popureb.A (Microsoft); Rootkit.Win32.Agent.bnba (Kaspersky); Generic.dx!zpj (Mcafee); Mal/Generic-L (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 malware uses complex routines to hide in the infected system's master boot record (MBR) in order to evade detection.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan may be dropped by other malware.

  TECHNICAL DETAILS

File Size:

6,656 bytes

File Type:

SYS

Memory Resident:

Yes

Initial Samples Received Date:

28 Jun 2011

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_POPUREB.SMA

Autostart Technique

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Service\hello_tt
ImagePath = "{malware path and file name}"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Alg = "%System Root%\alg.exe"

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

8.261.00

VSAPI OPR PATTERN Date:

02 Jul 2011

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

Remove malware/grayware files that dropped/downloaded RTKT_POPUREB.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\SYSTEM\CurrentControlSet\Service
    • hello_tt

Step 5

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
    • Alg = "%System Root%\alg.exe"

Step 6

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


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