Today, researchers at Check Point Security announced a new attack against WhatsApp and Telegram, targeting the way both chat services process images and multimedia files. Check Point was able to craft a malicious image that would appear normal in preview, but direct users to a malware-laden HTML page. Once loaded, the page will retrieve all locally stored data, enabling attackers to effectively hijack the user’s account.
“By simply sending an innocent looking photo, an attacker could gain control over the account, access message history, all photos that were ever shared, and send messages on behalf of the user,” said Oded Vanunu, head of product vulnerability research at Check Point.
Notably, the attack requires a user to purposefully open the sent file, making it less useful for botnets or mass surveillance. The vulnerability was reported to both WhatsApp and Telegram on March 8th, and both have since changed their systems to protect against similar. Neither company responded to a request for comment.
Unlike conventional email or chat services, WhatsApp and Telegram have no way of reading messages sent between users, a crucial part of the promise of end-to-end encryption. In this case, that promise may have made it easier for the malicious image to slip through. With no mechanism for intercepting messages in transit, it is far more difficult to scan for viruses or other malicious attacks sent using the service.
In November, Check Point uncovered a malware campaign that infected over 1 million Android phones to up-vote products in the Google Play store.