Slack · Report #210654
Bypass to postMessage origin validation via FTP
Validstatus
highseverity
15upvotes
21 Apr 2017disclosed
Summary
@a1kmm- discovered a bypass to our postMessage origin check, wherein an attacker with existing MITM capabilities could use FTP to bypass validation and view XOXS tokens of victims on the local network. This was related to, and investigated at the same time as, a previous report. This issue is now resolved and was not exploited. Thanks @a1kmm-!
How it was found
The write-up for this report has not been downloaded yet, or the program disclosed it without one. Read it on HackerOne.