An unpatched security weakness in Google Drive could be exploited by malware attackers to distribute malicious files disguised as legitimate documents or images, enabling bad actors to perform spear-phishing attacks comparatively with a high success rate.
The latest security issue—of which Google is aware but, unfortunately, left unpatched—resides in the “manage versions” functionality offered by Google Drive that allows users to upload and manage different versions of a file, as well as in the way its interface provides a new version of the files to the users.
Logically, the manage versions functionally should allow Google Drive users to update an older version of a file with a new version having the same file extension, but it turns out that it’s not the case.
According to A. Nikoci, a system administrator by profession who reported the flaw to Google and later disclosed it to The Hacker News, the affected functionally allows users to upload a new version with any file extension for any existing file on the cloud storage, even with a malicious executable.
As shown in the demo videos—which Nikoci shared exclusively with The Hacker News—in doing so, a legitimate version of the file that’s already been shared among a group of users can be replaced by a malicious file, which when previewed online doesn’t indicate newly made changes or raise any alarm, but when downloaded can be employed to infect targeted systems.
“Google lets you change the file version without checking if it’s the same type,” Nikoci said. “They did not even force the same extension.”
Needless to say, the issue leaves the door open for highly effective spear-phishing campaigns that take advantage of the widespread prevalence of cloud services such as Google Drive to distribute malware.
images from Hacker News