CVE-2024-2511: OpenSSL advisory

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

Issue summary: Some non-default TLS server configurations can cause unbounded memory growth when processing TLSv1.3 sessions Impact summary: An attacker may exploit certain server configurations to trigger unbounded memory growth that would lead to a Denial of Service This problem can occur in TLSv1.3 if the non-default SSL_OP_NO_TICKET option is being used (but not if early_data support is also configured and the default anti-replay protection is in use). In this case, under certain conditions, the session cache can get into an incorrect state and it will fail to flush properly as it fills. The session cache will continue to grow in an unbounded manner. A malicious client could deliberately create the scenario for this failure to force a Denial of Service. It may also happen by accident in normal operation. This issue only affects TLS servers supporting TLSv1.3. It does not affect TLS clients. The FIPS modules in 3.2, 3.1 and 3.0 are not affected by this issue. OpenSSL 1.0.2 is also not affected by this issue.

Description quoted from the CVE record (assigned by openssl, published 2024-04-08).

Weakness: CWE-1325 Improperly Controlled Sequential Memory Allocation

How it can be exploited

Exploitable over the network with high attack complexity needing no privileges and no user interaction. Impact: confidentiality none, integrity none, availability high. CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: partial.

Public exploit evidence (Exploit Observer)

Exploit Observer found 3 research write-ups naming this CVE.

Rapid7 analysis

See all 22 references on Exploit Observer

Live scores

EPSS: 0.593
very likely to be attacked soon
VEDAS: 0.981
strong exploit evidence
On CISA KEV: Not listed
Detection rule: No public rule yet

Who is affected

Product	Affected	Not affected
OpenSSL	from 3.2.0 before 3.2.2 from 3.1.0 before 3.1.6 from 3.0.0 before 3.0.14 from 1.1.1 before 1.1.1y	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

Fixed versions stated in the CVE record: 3.2.2, 3.1.6, 3.0.14, 1.1.1y.

Vendor guidance:

How to detect it

There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.

References

Vendor advisories and patches

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.