Microsoft stated on Wednesday that it lately recognized a vulnerability in TikTok’s Android app that might permit attackers to hijack accounts when customers did nothing greater than click on on a single errant hyperlink. The software program maker stated it notified TikTok of the vulnerability in February and that the China-based social media firm has since fastened the flaw, which is tracked as CVE-2022-28799.

The vulnerability resided in how the app verified what’s often known as deeplinks, that are Android-specific hyperlinks for accessing particular person elements inside a cellular app. Deeplinks should be declared in an app’s manifest to be used exterior of the app—so, for instance, somebody who clicks on a TikTok hyperlink in a browser has the content material mechanically opened within the TikTok app.

An app can even cryptographically declare the validity of a URL area. TikTok on Android, for example, declares the area m.tiktok.com. Normally, the TikTok app will permit content material from tiktok.com to be loaded into its WebView part however forbid WebView from loading content material from different domains.

“The vulnerability allowed the app’s deeplink verification to be bypassed,” the researchers wrote. “Attackers may power the app to load an arbitrary URL to the app’s WebView, permitting the URL to then entry the WebView’s connected JavaScript bridges and grant performance to attackers.”

The researchers went on to create a proof-of-concept exploit that did simply that. It concerned sending a focused TikTok consumer a malicious hyperlink that, when clicked, obtained the authentication tokens that TikTok servers require for customers to show possession of their account. The PoC hyperlink additionally modified the focused consumer’s profile bio to show the textual content “!! SECURITY BREACH !!”

“Once the attacker’s specifically crafted malicious hyperlink is clicked by the focused TikTok consumer, the attacker’s server, https://www.attacker[.]com/poc, is granted full entry to the JavaScript bridge and might invoke any uncovered performance,” the researchers wrote. “The attacker’s server returns an HTML web page containing JavaScript code to ship video add tokens again to the attacker in addition to change the consumer’s profile biography.”

Microsoft stated it has no proof the vulnerability was actively exploited within the wild.