OpenSIPS is a Session Initiation Protocol (SIP) server implementation.
CVE-2023-27601 is a high-severity improper input validation vulnerability in opensips, 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. Affected opensips versions: < 3.1.7; >= 3.2.0, < 3.2.4. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.99% chance of exploitation within 30 days, higher than 63% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of opensips you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- 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 the organisation that assigned the CVE. 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 | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
OpenSIPS is a Session Initiation Protocol (SIP) server implementation. Prior to versions 3.1.7 and 3.2.4, OpenSIPS crashes when a malformed SDP body is received and is processed by the `delete_sdp_line` function in the sipmsgops module. This issue can be reproduced by calling the function with an SDP body that does not terminate by a line feed (i.e. `\n`). The vulnerability was found while performing black-box fuzzing against an OpenSIPS server running a configuration that made use of the functions `codec_delete_except_re` and `codec_delete_re`. The same issue was also discovered while performing coverage guided fuzzing on the function `codec_delete_except_re`. The crash happens because the function `delete_sdp_line` expects that an SDP line is terminated by a line feed (`\n`): By abusing this vulnerability, an attacker is able to crash the server. It affects configurations containing functions that rely on the affected code, such as the function `codec_delete_except_re`. Due to the sanity check that is performed in the `del_lump` function, exploitation of this issue will generate an `abort` in the lumps processing function, resulting in a Denial of Service. This issue has been fixed in versions 3.1.7 and 3.2.4.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How developers prevent this class of flaw
- Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/OpenSIPS/opensips/commit/8f87c7c03da55f9c79bd92e67fa2c94b2a7ce5cfThird Party Advisory
Other vulnerabilities in opensips
- 7.3 High severity
- 8.7 High severity
- 8.7 High severity
- 9.1 Critical severity
- 7.5 High severity
- 9.1 Critical severity
Recent Improper Input Validation vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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