OPA: Authentication Bypass by Capture-replay
CVE-2024-8260 is a high-severity authentication bypass by capture-replay vulnerability in OPA from Styra, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. The record lists version v0.68.0 as the first without the flaw, so updating OPA to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.34% 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
- Update OPA to v0.68.0 or a later version.
- Update Open Policy Agent to 0.68.0 or a later version.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Styra | OPA | before v0.68.0 | v0.68.0 |
| Openpolicyagent | Open Policy Agent | before 0.68.0 | 0.68.0 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.1 | Medium | CNA (tenable.com) |
| CVSS 3.1 | 7.3 | High | NVD |
Official description
A SMB force-authentication vulnerability exists in all versions of OPA for Windows prior to v0.68.0. The vulnerability exists because of improper input validation, allowing a user to pass an arbitrary SMB share instead of a Rego file as an argument to OPA CLI or to one of the OPA Go library’s functions.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Capture-replay
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
How developers prevent this class of flaw
- Utilize some sequence or time stamping functionality along with a checksum which takes this into account in order to ensure that messages can be parsed only once.
- Since any attacker who can listen to traffic can see sequence numbers, it is necessary to sign messages with some kind of cryptography to ensure that sequence numbers are not simply doctored along with content.
More Authentication Bypass by Capture-replay vulnerabilities (CWE-294)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- tenable.com/security/research/tra-2024-36Third Party Advisory
Recent Authentication Bypass by Capture-replay vulnerabilities
- 8.2 High severity
- 8.4 High severity
- 8.7 High severity
- 8.1 High severity
- 7.8 High severity
- 8.1 High severity
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