WORM_NOHAD.B

 Analysis by: Abraham Latimer Camba

 ALIASES:

Trojan horse Agent4.BMSO (AVG), W32/Trojan2.OEMC (FProtect), Trojan.Win32.Agent.adtmi (Kaspersky), Worm:Win32/Nohad.A (Microsoft), W32/Autorun-FSV!A9AF2BEA4C1D (McAfee), Win32/AutoRun.Delf.QI worm (ESET), W32/Autorun.CL.worm (Panda), TR/Patched.Gen (Avira), Gen:Variant.Strictor.51483 (Bitdefender)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This worm arrives by connecting affected removable drives to a system. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

3,956,224 bytes

File Type:

EXE

Initial Samples Received Date:

12 Nov 2014

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It 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 worm adds the following folders:

  • %User Profile%\Documen

(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 drops the following copies of itself into the affected system and executes them:

  • %User Profile%\Documen\nod42.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.)

Autostart Technique

This worm drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\nottepad.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Other System Modifications

This worm 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.)

Propagation

This worm creates the following folders in all removable drives:

  • {drive letter}:\temp

It drops the following copy(ies) of itself in all removable drives:

  • {drive letter}:\temp\system.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
open=temp\system.exe


It drops copies of itself in removable drives. These copies use the names of the following items located on the said drives for their file names:

  • files and folders