Backdoor Lecna Exploits MS hcp URL XSS Vulnerability (July 1, 2010)

SonicWALL UTM Research received reports of malware actively exploiting the recently reported vulnerability in Windows Help and Support Center (CVE-2010-1885) – MS hcp-URL Cross Site Scripting (June 10, 2010)

The malware author used the code below to exploit the vulnerability:

Upon successful exploitation, it downloads a component JavaScript file shown below as its payload:

This file is being blocked by SonicWALL as GAV: JS.HCP.SVR.XSS (Exploit)

This script then downloads and executes the Backdoor Lecna file which uses an Adobe Acrobat icon to disguise itself as a acrobat file.

Malware Installation

Mutex Name:
To ensure that only one instance of this malware is running on the infected system it creates a mutex:

• MicrosoftForZR

Files Added:
It drops a copy in Startup folder which allows itself to run on every system startup.

• (Documents and Settings)All UsersStart MenuProgramsStartupAdobe Acrobat Speed Launcher.exe – GAV: Lecna.GEN (Trojan)

Registries Added:
It writes into the registry the host id which marks systems it successfully infected:

• Key: HKEY_LOCAL_MACHINESOFTWAREMicrosoftCurrentIESetup
  Value: hostid
  Data: dword:000045f2

Files Downloaded:
It downloads the following files which are actually executable.

• www.{REMOVED}.com/ForZRMail/myapp.htm – GAV: Lecna.GEN (Trojan)
• www.{REMOVED}.com/ForZRMail/zr.txt – GAV: Lecna.GEN_2 (Trojan)

Network Activity:
Tries to connect to the following:

• 77.90.80.0
• www.vic{REMOVED}.com
• www.ian{REMOVED}.com

SonicWALL Gateway AntiVirus provided protection against this malicious backdoor via following signatures:

• GAV: HCP.SVR.XSS.1 (Exploit)
• GAV: JS.HCP.SVR.XSS (Exploit)
• GAV: Lecna.GEN (Trojan)
• GAV: Lecna.GEN_2 (Trojan)

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The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.