The Signal app before 5.34 for iOS allows URI spoofing via RTLO injection. It incorrectly renders RTLO encoded URLs beginning with a non-breaking space, when there is a hash character in the URL. This technique allows a remote unauthenticated attacker to send legitimate looking links, appearing to be any website URL, by abusing the non-http/non-https automatic rendering of URLs. An attacker can spoof, for example, example.com, and masquerade any URL with a malicious destination. An attacker requires a subdomain such as gepj, txt, fdp, or xcod, which would appear backwards as jpeg, txt, pdf, and docx respectively.
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
| Link | Tags |
|---|---|
| https://github.com/zadewg/RIUS | third party advisory |
| https://sick.codes/sick-2022-42 | patch third party advisory exploit |
| https://github.com/sickcodes/security/blob/master/advisories/SICK-2022-42.md | patch third party advisory exploit |
| https://blog.malwarebytes.com/social-engineering/2022/03/uri-spoofing-flaw-could-phish-whatsapp-signal-instagram-and-imessage-users/ | third party advisory |