BKDR_ANDROM.YYSIZ

 Analysis by: Pearl Charlaine Espejo

 ALIASES:

Troj/Androm-GI (Sophos); Win32/TrojanDownloader.Wauchos.BD (ESET-NOD32); Worm:Win32/Gamarue (Microsoft); TR/AD.Gamarue.Y.1838 (Avira)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

276,108 bytes

File Type:

EXE

Initial Samples Received Date:

29 Jan 2016

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 the following copies of itself into the affected system:

  • %All Users Profile%\ms{random}.exe

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
{random number} = "%All Users Profile%\ms{random}.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
TaskbarNoNotification = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
TaskbarNoNotification = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
HideSCAHealth = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
HideSCAHealth = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
cval = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MpsSvc
Start = "4"

(Note: The default value data of the said registry entry is "2".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\SharedAccess
Start = "4"

(Note: The default value data of the said registry entry is "2".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WinDefend
Start = "4"

(Note: The default value data of the said registry entry is "2".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
Start = "4"

(Note: The default value data of the said registry entry is "2".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
Start = "4"

(Note: The default value data of the said registry entry is "2".)

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}dhi.com/andoluse.php
  • http://{BLOCKED}dertufun.xyz/css/ajax.php
  • http://www.{BLOCKED}ionelanza.it/eng/v3.exe
  • http://www.{BLOCKED}ionelanza.it/eng/akeyb.exe
  • http://www.{BLOCKED}artet.com/ff/serif/payload.exe

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.304.07

FIRST VSAPI PATTERN DATE:

29 Jan 2016

VSAPI OPR PATTERN File:

12.305.00

VSAPI OPR PATTERN Date:

30 Jan 2016

NOTES:

Trend customers:

    Keep your pattern and scan engine files updated. Trend Micro antivirus software can clean or remove most types of computer threats. Malware, though, such as Trojans, scripts, overwriting viruses and joke programs which are identified as uncleanable, should simply be deleted.

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  • Use HouseCall - the Trend Micro online threat scanner to check for malware that may already be on your PC.
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