The antivirus scanning engine used in virtually every Trend Micro product is plagued by a critical flaw that can be used by attackers to take down or hijack PCs, several security organizations said today. A patch has been issued by Trend Micro to plug the hole.
The bug, which can be exploited by getting the scanning engine to process a malformed UPX compressed executable file, can cause a buffer overflow on systems running the Tokyo-based company's Client Server, InterScan, OfficeScan, PC-cillin, ScanMail and ServerProtect product lines, according to Danish vulnerability tracker Secunia and French counterpart, FrSIRT. The two pegged the risk as "Extremely Critical" and "Critical," respectively.
VeriSign iDefense, which was credited with the discovery of the flaw, noted in an online advisory that no authentication was needed by the attacker and a successful attack would allow "complete control of the affected system." iDefense first reported the vulnerability to Trend Micro on Jan. 17.
Antivirus rival Symantec added that an attack could come from several directions, including a Web site or an e-mail message. "Multiple remote vectors could be employed to passively exploit this issue...because the [scanning] engine may be applied against network streams, or automatically applied against e-mail attachments at gateways," Symantec warned subscribers to its DeepSight threat management network.
Trend Micro has issued a signature update that patches the UPX parsing algorithm and includes generic detection for malicious UPX files. A permanent patch will be applied to the scanning engine when it upgrades to version 8.5 in the future. The update can be retrieved manually using the instructions posted on the Trend Web site, or automatically through the products' auto-updater.
A spokesman for Trend, however, was unable to immediately confirm that all users who have automatic updating enabled have received the patch.
Virtually every major antivirus vendor has had to patch vulnerabilities in its security software. Symantec, which saw its own scanning engine marked for attack in 2005, downplayed the threat to Trend Micro users -- even as it hedged its bet. "This type of vulnerability has not been widely exploited in the wild in the past," its DeepSight alert read. "However, developments in kernel-based payloads for publicly available frameworks, such as the Metasploit framework, may expedite the creation of an exploit for this issue."