Pierluigi Paganini August 23, 2020

A bug in Google Drive could be exploited by threat actors to distribute malicious files disguised as legitimate documents or images.

An unpatched weakness in Google Drive could be exploited by threat actors to distribute weaponized files disguised as legitimate documents or images.

enabling bad actors to perform spear-phishing attacks comparatively with a high success rate.

The issue resides in the “manage versions” feature implemented in Google Drive allows users to upload and manage different versions of a file and in the interface that allows users to provides a new version of the files to the users.

The “manage versions” feature was designed to allow Google Drive users to update an older version of a file with a new one having the same file extension, unfortunately, this is not true.

The researchers A. Nikoci, discovered that the functionally allows users to upload a new version with any file extension for any file stored on Google Drive, allowing the upload of malicious executables.

“Google lets you change the file version without checking if it’s the same type,” Nikoci explained. “They did not even force the same extension.”

The researchers reported the issue to Google and shared his findings with TheHackerNews that published the following videos that show how to exploit the weakness.

“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.” reads the post published by THN.

An attacker could exploit the weakness to carry out spear-phishing campaigns using messages that include links to malicious files hosted on Google Drive. Using links to files stored on popular cloud storage is a known tactic used by threat actors to carry out effective phishing campaigns

Experts pointed out that Google Chrome appears to implicitly trust any file downloaded from Google Drive, even if they are flagged and “malicious” by antivirus software as malicious.

Google recently addressed an email spoofing vulnerability affecting Gmail and G Suite a few hours after it was publicly disclosed. The vulnerability is caused by missing verifications when configuring mail routes. The issue could have been exploited by an attacker to send an email that appears as sent by another Gmail or G Suite user, the message is able to bypass protection mechanisms such as Sender Policy Framework (SPF) and Domain-based Message Authentication, Reporting and Conformance (DMARC).

At the time of writing, there is no evidence that the vulnerability has been exploited by threat actors in attacks in the wild.

Pierluigi Paganini

(SecurityAffairs – hacking, Google Drive)

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