Accounts on Google Inc.'s Gmail can be easily hacked, allowing any past -- and future e-mail messages -- to be forwarded to the attacker's own in-box, a vulnerability researcher said yesterday.
Dubbed a "cross-site request forgery" (CSRF), the Gmail bug was disclosed Tuesday by Petko Petkov, a U.K.-based Web vulnerability penetration tester who has made a name for himself of late. In the past two weeks, Petkov has publicly posted information about critical, zero-day bugs in Apple Inc.'s QuickTime, Microsoft Corp.'s Windows Media Player and Adobe Systems Inc.'s Portable Document Format (PDF).
According to Petkov, who declined to release details about the vulnerability, attackers can use Gmail's filtering feature to exploit the bug. An attack, he said, would start with a victim visiting a malicious Web site while also still logged into his Gmail account. The malicious site would then perform what Petkov called a "multipart/form-date POST" -- an HTML command that can be used to upload files -- to one of the Gmail application programming interfaces, then inject a rogue filter into the user's filter list.
Petkov posted a series of screenshots on the Gnucitizen.org site that illustrated one possible attack. "In the example, the attacker writes a filter, which simply looks for e-mails with attachments and forwards them to an e-mail of their choice," Petkov said. "This filter will automatically transfer all e-mails matching the rule.