Libreswan: NULL Pointer Dereference
CVE-2022-23094 is a high-severity NULL pointer dereference vulnerability in Libreswan, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 4.6 as the first without the flaw, so updating Libreswan to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.63% chance of exploitation within 30 days, higher than 86% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Libreswan to 4.6 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Libreswan | Libreswan | 4.2 up to, but not including, 4.6 | 4.6 |
| Fedora Project | Fedora | 34; 35 | Not stated |
| Debian | Debian Linux | 10.0 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
Libreswan 4.2 through 4.5 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted IKEv1 packet because pluto/ikev1.c wrongly expects that a state object exists. This is fixed in 4.6.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL.
How developers prevent this class of flaw
- For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
- Select a programming language that is not susceptible to these issues.
- Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- libreswan.org/security/CVE-2022-23094Third Party Advisory
- debian.org/security/2022/dsa-5048Third Party Advisory
Technical write-ups (may include proof of concept)
- github.com/libreswan/libreswan/issues/585Exploit, Issue Tracking, Third Party Advisory
Other references
Other vulnerabilities in Libreswan
- 7.5 High severity
- 7.5 High severity
Recent NULL Pointer Dereference vulnerabilities
- 7.8 High severity
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