Popular BitTorrent client µTorrent has quietly patched a vulnerability that created a means for hackers to load malware onto the PCs of file-sharers simply by persuading them to open a poisoned Torrent.
The Hollywood-dream bug stemmed from a stack-based buffer overflow vulnerability and offered far more potential for mischief than either salted (empty or impossible to play) files or media files that attempt to induce users to install fake codecs (often contaminated with malware) once users attempt to play downloaded content.
The vulnerability has been confirmed in version 1.7.7 of µTorrent. Earlier versions may also be buggy. News of the bug emerged in a posting by Rhys Kidd to a security mailing list on Monday. He claims that the flaw had been present as a zero-day vulnerability in the software for the last two years.
BitTorrent Mainline version six and beyond are also vulnerable because BitTorrent, Inc. makes use of µTorrent source code, he adds. The two software packages make up over 18.8 per cent on the installed P2P client base, creating plenty of scope for shenanigans even though the bug would have been far from straightforward to misuse.
"Reliable exploitation is difficult although not impossible," notes Kidd in a detailed advisory on the bug.
Fortunately a major new version of µTorrent, released earlier this month, squashes the bug, even if release notes fail to mention this point. Version 1.8 RC7 of the software silently patched the flaw, according to security notification service Secunia, which advises users to update to version 1.8.0 of µTorrent. BitTorrent is also vulnerable but yet to deliver a patch, Secunia reports. ®