Rango Antivirus FakeAV makes a surge (Oct 31, 2014)

The Dell Sonicwall Threats Research team has observed a huge wave of spam that is spreading FakeAV software called Rango Antivirus 2014. FakeAV software was a big trend 2 years ago but had since died down following a rise of infostealer trojans and ransomware such as Cryptolocker. This FakeAV Trojan arrives as an email with an attachment masquerading as a court notice document.

Infection cycle:

The Trojan adds the following files to the filesystem:

• %APPDATA%ipcsxnep.exe [Detected as GAV: Zbot.CH_4 (Trojan)]
• %APPDATA%upoosook.exe [Detected as GAV: Inject.C_2 (Trojan)]

The Trojan adds the following keys to the Windows registry:

• HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun rqvobwcf “%APPDATA%ipcsxnep.exe”
• HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun xwpdlhad “%APPDATA%upoosook.exe”

The Trojan runs an instance of svchost.exe and injects malicious code into it. The malicious code causes it to download an encrypted copy of ipcsxnep.exe from a remote webserver:

The following strings where seen in the svchost memory space. Some of this system information is sent encrypted in the initial POST request:

The Trojan then sleeps for a variable period of time. We observed a period of around 10-15 minutes before FakeAV dialogs were shown. The following is a sample of the dialogs that are shown to the user:

As seen in the screenshots, the Trojan uses the usual FakeAV scare tactics to entice the user into paying for the software. The payment page shows 3 license packages:

SonicWALL Gateway AntiVirus provides protection against this threat via the following signatures:

• GAV: Zbot.CH_3 (Trojan)
• GAV: Zbot.CH_4 (Trojan)
• GAV: Inject.C_2 (Trojan)

Security News

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.