Cybersecurity researchers have found a safety flaw in Microsoft’s OneDrive File Picker that, if efficiently exploited, may permit web sites to entry a consumer’s whole cloud storage content material, versus simply the recordsdata chosen for add through the software.
“This stems from overly broad OAuth scopes and deceptive consent screens that fail to obviously clarify the extent of entry being granted,” the Oasis Analysis Staff mentioned in a report shared with The Hacker Information. “This flaw may have extreme penalties, together with buyer knowledge leakage and violation of compliance rules.”
It is assessed that a number of apps are affected, akin to ChatGPT, Slack, Trello, and ClickUp, given their integration with Microsoft’s cloud service.
The issue, Oasis mentioned, is the results of extreme permissions requested by the OneDrive File Picker, which seeks learn entry to all the drive, even in instances solely a single file is uploaded as a result of absence of fine-grained OAuth scopes for OneDrive.
Compounding issues additional, the consent immediate customers are introduced with previous to a file add is obscure and doesn’t adequately convey the extent of entry being granted, thereby exposing customers to surprising safety dangers.
“The shortage of fine-grained scopes makes it inconceivable for customers to differentiate between malicious apps that focus on all recordsdata and legit apps that ask for extreme permissions just because there isn’t a different safe possibility,” Oasis famous.
The New York-based safety firm additional identified that the OAuth tokens used to authorize entry are sometimes saved insecurely, including they’re saved within the browser’s session storage in plaintext format.
One other potential pitfall is that the authorization workflows might also contain issuing a refresh token, granting the applying ongoing entry to consumer knowledge by permitting it to get new entry tokens with out having to ask the consumer to log in once more when the present token expires.
Following accountable disclosure, Microsoft has acknowledged the issue, though there isn’t a repair as but. Within the interim, it is value contemplating quickly eradicating the choice to add recordsdata utilizing OneDrive via OAuth till a safe various is in place. Alternately, it is suggested to keep away from utilizing refresh tokens and retailer entry tokens in a safe method and do away with them when now not wanted.
The Hacker Information has reached out to Microsoft for additional remark, and we’ll replace the story if we hear again.
“The shortage of fine-grained OAuth scopes mixed with Microsoft’s obscure consumer immediate is a harmful mixture that places each private and enterprise customers in danger,” Oasis mentioned. “This discovery reinforces the significance of steady vigilance in OAuth scope administration, common safety assessments, and proactive monitoring to guard consumer knowledge.”
