Modified by: Michael Cabel
ALIASES:

Trojan:Win32/Rimecud.A (Microsoft); W32/Rimecud.gen.dp (McAfee); Trojan.Win32.Rimecud.ag (v) (Sunbelt)

 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: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This malware disguises itself as a Trend Micro product/component. It drops a bitcoin-mining malware.

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

For the related story, you may read the blog post Trojan Disguised as Trend Micro Component Drops Bitcoin-Mining Malware

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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 84,480 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 17 Nov 2012
Payload: Downloads files

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:

  • %User Profile%\{Random File Name}.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

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

  • svchost.exe

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = "%User Profile%\{Random File Name}.exe"

Download Routine

This Trojan accesses the following websites to download files:

  • {BLOCKED}a.betrule.com
  • {BLOCKED}a.agesask.net
  • {BLOCKED}a.agesonest.com

Trend Micro detects the dowloaded file as:

  • HKTL_BITCOINMINE

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.530.03
FIRST VSAPI PATTERN DATE: 16 Nov 2012
VSAPI OPR PATTERN File: 9.531.00
VSAPI OPR PATTERN Date: 17 Nov 2012

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

Remove the malware/grayware file dropped/downloaded by TROJ_RIMECUD.AJL

Step 3

Identify and delete files detected as TROJ_RIMECUD.AJL using the Recovery Console

[ Learn More ]

Step 4

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 NT\CurrentVersion\Winlogon
    • Taskman = %User Profile%\{Random File Name}.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_RIMECUD.AJL. 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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