TROJ_DROPPR.CXC

July 14, 2015
 Analysis by: Francis Xavier Antazo
 ALIASES:

Trojan:Win32/Foosace.H!dha (Microsoft), Exploit.Win32.Sofacy.b (Kaspersky), Trojan.Sofacy (Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This is the detection for the second stage malware related to the new Java zero-day exploit which was used in the targeted attack campaign, Operation Pawn Storm. In the second stage of the attack, it downloads this malware, which serves as a dropper of .DLL file detected as TSPY_SEDNIT.C.

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

Operation Pawn Storm is an APT campaign that targeted military and defense contractors from the US and its allies among others. For more details on this targeted attack, read our entry, An In-Depth Look at How Pawn Storm’s Java Zero-Day Was Used.

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.

  TECHNICAL DETAILS

File Size:

1619968 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Jul 2015

Payload:

Drops 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 component file(s):

  • %User Temp%\jhuhugit.temp
  • %Application Data%\fvecer.bat - used to load TSPY_SEDNIT.C
  • %Application Data%\api-ms-win-downlevel-profile-l1-1-0.dll - detected as TSPY_SEDNIT.C

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following processes:

  • rundll32.exe - to load TSPY_SEDNIT.C

Autostart Technique

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

HKEY_CURRENT_USER\Environment
UserInitMprLogonScript = "%Application Data%\fvecer.bat"

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.784.08

FIRST VSAPI PATTERN DATE:

11 Jul 2015

VSAPI OPR PATTERN File:

11.785.00

VSAPI OPR PATTERN Date:

12 Jul 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ 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_CURRENT_USER\Environment
    • UserInitMprLogonScript = "%Application Data%\fvecer.bat"

Step 5

Remove malware/grayware files dropped/downloaded by TROJ_DROPPR.CXC . (Note: Please skip this step if the threats listed below have already been removed.)

    • TSPY_SEDNIT.C

Step 6

Search and delete these files

[ Learn More ]
There may be some 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%\jhuhugit.temp
  • %Application Data%\fvecer.bat

Step 7

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