Specialists from Tenable company disovered vulnerability in Windows-version of corporate Slack messenger (version 3.3.7) that enables changing file upload destination and steal files, change them or add malware programs.The problem is in implementation of the protocol handler “slack://” in the application. With the use of specially formed link, published in Slack-channel, attacker can modify client’s setting, for example, change folder for download and point to folder that he controls. If victim follows the link, all downloads will get on the attacker’s SMB-server.
After changing of the established by default folder for downloads attacker can only steal the document, but also implement in it malware code. If user opens such document, his device will be infected, explained specialist David Wells.
At the same time, for successful implementation of URL attacker will even not have to subscribe on Slack-channel – link can get in channel through RSS-feed.
“I can publish a post in popular society Reddit; Slack users from all over the world are subscribed on it. This publication will include web-link, that will redirect user on the malware slack:// and will change settings if clicking on it”, – says Wells.
As it is noted, in similar situation will be shown notification that link initiates Slack start, so attack will be impossible, if user will not provide his agreement.
Slack team have already released fixed Slack 3.4.0 version for Windows. All users are recommended to install updates ASAP.