Information disclosure in Tencent WeChat

1) Out-of-bounds read

EUVDB-ID: #VU51003

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-27247

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: No

Description

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

The vulnerability exists due to a boundary condition within the WXAM decoder. A remote attacker can create a specially crafted file, trick the victim into opening it, trigger out-of-bounds read error and read contents of memory on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

WeChat: before 3.1.0

External links

http://www.zerodayinitiative.com/advisories/ZDI-21-217/

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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