istio: Always-Incorrect Control Flow Implementation
CVE-2022-21679 is a critical-severity always-incorrect control flow implementation vulnerability in istio, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected istio versions: >= 1.12.0, < 1.12.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.1% chance of exploitation within 30 days, higher than 66% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of istio 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
- 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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.8 | Medium | CNA (github.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 2.0 | 7.5 | High | NVD |
Official description
Istio is an open platform to connect, manage, and secure microservices. In Istio 1.12.0 and 1.12.1 The authorization policy with hosts and notHosts might be accidentally bypassed for ALLOW action or rejected unexpectedly for DENY action during the upgrade from 1.11 to 1.12.0/1.12.1. Istio 1.12 supports the hosts and notHosts fields in authorization policy with a new Envoy API shipped with the 1.12 data plane. A bug in the 1.12.0 and 1.12.1 incorrectly uses the new Envoy API with the 1.11 data plane. This will cause the hosts and notHosts fields to be always matched regardless of the actual value of the host header when mixing 1.12.0/1.12.1 control plane and 1.11 data plane. Users are advised to upgrade or to not mix the 1.12.0/1.12.1 control plane with 1.11 data plane if using hosts or notHosts field in authorization policy.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Always-Incorrect Control Flow Implementation
The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated.
More Always-Incorrect Control Flow Implementation vulnerabilities (CWE-670)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/istio/istio/security/advisories/GHSA-rwfr-xrvw-2rvvThird Party Advisory
- istio.io/latest/news/releases/1.12.x/announcing-1.12.2/Release Notes
Other vulnerabilities in istio
- 7.7 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
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