go-saml: Improper Authentication
CVE-2023-48703 is a high-severity improper authentication vulnerability in go-saml from RobotsAndPencils, 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 go-saml versions: <= 0.0.0-20230606195814-29020529affc; 0.0.0-20230606195814-29020529affc 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 0.56% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of go-saml 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| RobotsAndPencils | go-saml | <= 0.0.0-20230606195814-29020529affc; 0.0.0-20230606195814-29020529affc and earlier | Not stated |
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
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CNA (github.com).
Official description
RobotsAndPencils go-saml, a SAML client library written in Go, contains an authentication bypass vulnerability in all known versions. This is due to how the `xmlsec1` command line tool is called internally to verify the signature of SAML assertions. When `xmlsec1` is used without defining the enabled key data, the origin of the public key for the signature verification is, unfortunately, not restricted. That means an attacker can sign the SAML assertions themselves and provide the required public key (e.g. an RSA key) directly embedded in the SAML token. Projects still using RobotsAndPencils/go-saml should move to another SAML library or alternatively remove support for SAML from their projects. The vulnerability can likely temporarily be fixed by forking the go-saml project and adding the command line argument `--enabled-key-data` and specifying a value such as `x509` or `raw-x509-cert` when calling the `xmlsec1` binary in the verify function. Please note that this workaround must be carefully tested before it can be used.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- securitylab.github.com/advisories/GHSL-2023-121_go-saml__archived_/Technical Description, Third Party Advisory
Recent Improper Authentication vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 9.6 Critical severity
Spotted an error? Tell us.