Gumblar Google-poisoning attack morphs

A Web attack that poisons Google search results is getting worse, according to security researchers.

The attack first relies on compromising normally legitimate website and planting malicious scripts. US CERT reports that stolen FTP credentials are reckoned to be the main technique in play during this stage of the attack but poor configuration settings and vulnerable web applications might also play a part.

Surfers who visit compromised websites are exposed to attacks that rely on well-known PDF and Flash Player vulnerabilities to plant malware onto Windows PCs.

This malware is designed to redirect Google search results as well as to swipe sensitive information from compromised machines, according to early findings from ongoing analysis.

The SANS Institute's Internet Storm Centre (ISC) adds that the attack has been around for some time but has intensified over recent days. Initially the malware was served up onto vulnerable Windows clients from the website gumblar.cn, which has been offline since Friday. A second domain - martuz.cn - has taken over this key role in the attack, ISC reports.

Web security scanning firm ScanSafe, which was among the first to warn of the rise of the attack, notes that the reference to martuz.cn in more recent attacks has been obfuscated, possibly in an attempt to thwart rudimentary blacklists. "The URI resulting from the injected script might appear as mar"+"tuz.cn instead of just martuz.cn," writes ScanSafe researcher Mary Landesman.

ScanSafe reported on Monday that Gumblar more than trebled (up 246 per cent) over the preceding week. It describes Gumblar as a botnet of compromised websites in a series of blog postings on the attack, which can be found here. Sophos reckons the Gumblar-related malware appeared in 42 per cent of all the newly infected websites it detected last week.

Unmask Parasites has published a more detailed take on the script associated with the attack, named Gumblar after the name of the first domain associated with the assault, here. ®