Exploit:Java/Blackhole

Summary

Exploit:Java/Blackhole identifies a Java class module used as part of an exploit kit known as Blackhole.

Disinfection & Removal

Prevention

This exploit targets a known vulnerability in Java; to prevent successful exploitation, please ensure you install the latest updates available and/or remove any old, unnecessary installations.

For the latest updates, please refer to the vendor site:

• Java Downloads for All Operating Systems

Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.

Technical Details

Exploit:Java/Blackhole identifies an exploit file used to exploit vulnerable installations of the the Java Runtime Environment (JRE).

Update: A related detection, Trojan.script.478415, identifies scripts found in the HTML files delivered as attachments to spam e-mails sent out by the Blackhole exploit kit. These attachments use misleading file names such as:

• invoices-[variable number].htm
• HP-Scan-[variable number].htm
• HP-Document-[variable number].htm
• Delivery Status Notification

The Blackhole exploit kit

The exploit file is delivered by the highly-prevalent Blackhole exploit kit, a utility program used by attackers to silently install their malware onto a user's computer during a drive-by download attack.

The exploit kit is typically hosted on a short-lived webpage, and victims are driven to these pages by either hijacking traffic from a legitimate, compromised website, by redirecting traffic from search engines using Search Engine Optimization (SEO) poisoning, or through malicious links in spam emails.

Once a visitor is on the malicious page, the exploit kit silently probes the visitor's computer system for vulnerabilities in specific applications (in some cases, specific versions of these applications). Targeted applications include JRE, Media Player, Adobe Flash Player and Adobe Reader, and specific Windows components.

If found, the kit automatically exploits the vulnerabilities and downloads additional files (the kit's payload) onto the victim machine. The files downloaded by Blackhole onto the victim machine are usually other known malware, including:

• Trojan-Spy:W32/Zbot
• Rootkit:W32/ZAccess
• Trojan-PWS:W32/Sinowal
• Backdoor:W32/TDSS

For more information:

• Labs Weblog: Java Considered Harmful
• Threat Report H1 2012 (PDF)