#VU77059 Server-Side Request Forgery (SSRF) in Synapse - CVE-2023-32683

Vulnerability identifier: #VU77059

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-32683

CWE-ID: CWE-918

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Synapse
Server applications / Conferencing, Collaboration and VoIP solutions

Vendor: Matrix.org

Description

The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input within the oEmbed and image URLs. A remote attacker can send a specially crafted HTTP request and trick the application to initiate requests to arbitrary systems.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Synapse: 1.0.0 - 1.84.1

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External links
https://github.com/matrix-org/synapse/security/advisories/GHSA-98px-6486-j7qc
https://github.com/matrix-org/synapse/pull/15601
https://github.com/matrix-org/synapse/releases/tag/v1.85.0

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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.