Open5gs: Reachable Assertion
CVE-2023-37019 is a high-severity reachable assertion vulnerability in Open5gs, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Open5gs versions: 2.6.4 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.81% chance of exploitation within 30 days, higher than 58% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Open5gs you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:N/I:N/A:H. Scored by CISA (ADP).
Official description
Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `S1Setup Request` message missing a required `Supported TAs` field to repeatedly crash the MME, resulting in denial of service.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reachable Assertion
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
How developers prevent this class of flaw
- If the assertion statement is required (e.g., for security or reliability), change the invoking code to avoid the conditions that trigger the assertion.
- Consider changing the assertion to some other less fatal error. This might not be easy to implement, since other code may be needed to handle the error.
- Make sensitive open/close operations non-reachable from directly user-controlled data (e.g. open/close resources)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- cellularsecurity.org/ransackedExploit, Technical Description, Third Party Advisory
Other vulnerabilities in Open5gs
- 7.5 High severity
- 8.3 High severity
- 7.4 High severity
- 7.4 High severity
- 8.6 High severity
- 7.3 High severity
Recent Reachable Assertion vulnerabilities
- 8.6 High severity
- 8.6 High severity
- 7.5 High severity
- 8.6 High severity
- 8.6 High severity
- 8.6 High severity
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