OSX_FLASHBCK.DL

February 27, 2012
 Analysis by: Christopher Daniel So
 PLATFORM:

Mac OS X

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This malware is the Flashback Mac Trojan Horse that installed by exploiting two certain Java vulnerabilities.

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.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

Mach-O

Initial Samples Received Date:

24 Feb 2012

Payload:

Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

  • JAVA_DROPPR.IC

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}6.139.211/jcounter/

It saves the files it downloads using the following names:

  • /tmp/.tdem

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

As of this writing, the said sites are inaccessible.

Other Details

This Trojan deletes itself after execution.

NOTES:

It does not perform its download routine if one of the following files or folders are present:

  • /Library/Little Snitch
  • /Developer/Applications/Xcode.app/Contents/MacOS/Xcode

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.800.05

FIRST VSAPI PATTERN DATE:

26 Feb 2012

VSAPI OPR PATTERN File:

8.801.00

VSAPI OPR PATTERN Date:

26 Feb 2012

Step 1

Remove the malware/grayware file that dropped/downloaded OSX_FLASHBCK.DL

Step 2

Scan your computer with your Trend Micro product to delete files detected as OSX_FLASHBCK.DL. 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.

NOTES:

To delete the downloaded file:

  1. Open a Terminal window. To open a terminal window, double-click Applications > Utilities > Terminal in Finder.
  2. In the Terminal window, type the following command:
    rm /tmp/.tdem
  3. Close Terminal by pressing ⌘ (Command) + Q.


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