Security Experts:

Latest PDF Exploit Targets Uyghur, Tibetan Activists

Attackers are using a new Adobe Reader exploit to target Tibetan and Uyghur activists to drop an advanced piece of malware, according to researchers from AlienVault and Kaspersky Lab.

The spear phishing campaign appears to be targeting Uyghur activists in Central Asia and activists in Tibet, Jamie Blasco, lab manager for AlienVault Labs, wrote in a blog post today. The timing of the attacks may coincide with the human rights conference kicking off this week in Geneva, Costin Raiu, senior security researcher at Kaspersky Lab, wrote in a parallel analysis on SecureList.

"Based on the lures we found it seems the same group is targeting both Tibet and Uyghyr activists in the same campaign," Blasco wrote.

Researchers have identified three malicious PDF files used in the latest attack, of which one looks like a New Year's party invitation and the other pretends to be a reimbursement authorization form, Blasco said. When the user opened the booby-trapped PDF document, the malicious code exploited the same PDF vulnerability (CVE-2013-0640) which had been exploited in a series of attacks against European government agencies back in February.

The PDF vulnerability is the first confirmed sandbox bypass for Adobe Reader and was patched by Adobe on Feb. 20.

The malware has "a lot of functionality to monitor and steal data from the infected system," Blasco said.

The earlier attack was first discovered by FireEye and has been dubbed "ItaDuke." The JavaScript code used in the PDF files sent during the latest attack bear some resemblance to the "ItaDuke" attacks, but there are some differences, Blasco said. Parts of the initial variables and obfuscation appear to have been removed from the original, Raiu said.

The current malware was digitally signed with a stolen certificate and communicated with a remote command-and-control server based in the Shandong province of China. The stolen certificate has since been revoked by the issuer, Raiu said.

“Based on the exploit code and the payloads that are being used in the attack, it is clear that the group is a different one,” Blasco said.

However, Raiu noted that some of the techniques built into the attack resemble the Tilde platform used to craft Duqu and Stuxnet."The threat actors behind these attacks are very active and continuously use new methods and new exploits to attack their victims," Raiu said. He also noted that Kaspersky Lab has seen several attacks targeting Uyghur and Tibetan activists in the past year.

As the first known exploit capable of bypassing the much-vaunted sandbox technology built into Adobe Reader X, the PDF exploit is "extremely valuable" to attackers, Raiu said. While the odds are likely that the malware originally developed by a nation-state, or it was built for the nation-state's use, the malware can now be copied and reused by other motivated cyber-criminals. "This is becoming a common procedure nowadays and we can expect more such piggybacking or exploit stealing in the future," Raiu said.

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Fahmida Y. Rashid is a Senior Contributing Writer for SecurityWeek. She has experience writing and reviewing security, core Internet infrastructure, open source, networking, and storage. Before setting out her journalism shingle, she spent nine years as a help-desk technician, software and Web application developer, network administrator, and technology consultant.