WORM_DELF.CHI

 Analysis by: Francis Xavier Antazo

 ALIASES:

Worm:Win32/Hamweq.A (MICROSOFT), a variant of Win32/Injector.EJF trojan (NOD32), HEUR:Trojan.Win32.Generic (KASPERSKY)

 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 via removable drives. 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:

33,420 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

19 Jul 2009

Arrival Details

This worm arrives via removable drives.

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 drops the following files:

  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\Desktop.ini

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It drops the following copies of itself into the affected system:

  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %System Root%\RECYCLER\
  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Propagation

This worm creates the following folders in all removable drives:

  • {Removable Drive Letter}:\RECYCLER\
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\

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

  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.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=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
shell\open\default=1