#VU53312 Resource exhaustion in Prosody - CVE-2021-32920

Vulnerability identifier: #VU53312

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-32920

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Prosody
Server applications / Mail servers

Vendor: Prosody

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to application does not properly control consumption of internal resources. A remote attacker can trigger resource exhaustion via a flood of SSL/TLS renegotiation requests and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Prosody: 0.11.0 - 0.11.8

---

External links
https://blog.prosody.im/prosody-0.11.9-released/
https://www.openwall.com/lists/oss-security/2021/05/13/1
https://www.openwall.com/lists/oss-security/2021/05/14/2

---

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.