Information disclosure in Signal Private Messenger for iOS and Android

1) Information disclosure

EUVDB-ID: #VU28172

Risk: Low

CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-5753

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to application discloses currently used DNS server to arbitrary user from non-contact list. The issue is related to how WebRTC processes ICE Candidates, which takes place before a user decides to answer an incoming Signal call. A remote attacker can gain access to victim's current DNS server IP address and based on this data uncover victim's geographical location.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Signal Private Messenger for Android: 4.59.0

Signal Private Messenger for iOS: 3.8.1.5

External links

http://www.tenable.com/security/research/tra-2020-33

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to perform certain actions on the device.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.