CVE-2021-41794

07.10.2021, 15:15

ogs_fqdn_parse in Open5GS 1.0.0 through 2.3.3 inappropriately trusts a client-supplied length value, leading to a buffer overflow. The attacker can send a PFCP Session Establishment Request with "internet" as the PDI Network Instance. The first character is interpreted as a length value to be used in a memcpy call. The destination buffer is only 100 bytes long on the stack. Then, 'i' gets interpreted as 105 bytes to copy from the source buffer to the destination buffer.

Classic Buffer Overflow

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	NIST	7.5 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
mitre	CNA	---				---
CVE	ADP	---				---

Base Score

CVSS 3.x

EPSS Score

Percentile: 59%

Vendor	Product	Version
open5gs	open5gs	1.0.0 ≤ 𝑥 ≤ 2.3.3

𝑥

= Vulnerable software versions

Known Exploits!

Common Weakness Enumeration

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
The program copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.

References

https://research.nccgroup.com/2021/10/06/technical-advisory-open5gs-stack-buffer-overflow-during-pfcp-session-establishment-on-upf-cve-2021-41794