PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

HELOAG is a family of backdoors. Spotted in 2010, HELOAG comes as a downloaded file from two specific sites.

HELOAG connects to a server and performs commands issued from the server. It connects to different IP addresses, depending on what the IP address the server feeds HELOAG.

  TECHNICAL DETAILS

Memory Resident: Yes
Payload: Connects to URLs/IPs

Installation

This backdoor drops the following copies of itself into the affected system:

  • %Windows%\ThunderUpdate.exe
  • %Windows%\csrse.exe
  • %Windows%\conme.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_SSDT_TOOL\
0000
Service = "SSDT_TOOL"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SSDT_TOOL
ImagePath = "\??\{malware path}\SSDT_TOOL.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SSDT_TOOL
DisplayName = "SSDT_TOOL"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SSDT_TOOL\Security
Security = "{hex values}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SSDT_TOOL\Enum
0 = "Root\LEGACY_SSDT_TOOL\0000"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe %Windows%\ThunderUpdate.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe %Windows%\csrse.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe %Windows%\conme.exe asds"

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This backdoor adds the following registry entries:

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

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\SuperHidden
UncheckedValue = "0"

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

Other Details

This backdoor connects to the following possibly malicious URL:

  • cnc{BLOCKED}e.ln.cn
  • {BLOCKED}.{BLOCKED}.130.247
  • http://www.{BLOCKED}m.com/reques0.asp?kind=020&mac={data}&key={random}