Amazon Ssm Agent: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2022-29527 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Amazon Ssm Agent from Amazon, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 3.1.1208.0 as the first without the flaw, so updating Amazon Ssm Agent to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% 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 Amazon Ssm Agent to 3.1.1208.0 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Amazon | Amazon Ssm Agent | before 3.1.1208.0 | 3.1.1208.0 |
Version data comes from NVD's product matching. 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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- 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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | NVD |
| CVSS 2.0 | 6.9 | Medium | NVD |
Official description
Amazon AWS amazon-ssm-agent before 3.1.1208.0 creates a world-writable sudoers file, which allows local attackers to inject Sudo rules and escalate privileges to root. This occurs in certain situations involving a race condition.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How developers prevent this class of flaw
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Use thread-safe capabilities such as the data access abstraction in Spring.
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/aws/amazon-ssm-agent/commit/0fe8ae99b2ff25649c7b86d3bc05fc037400aca7Third Party Advisory
- github.com/aws/amazon-ssm-agent/releases/tag/3.1.1208.0Release Notes, Third Party Advisory
Technical write-ups (may include proof of concept)
- bugzilla.suse.com/show_bug.cgi?id=1196556Exploit, Issue Tracking, Third Party Advisory
Other vulnerabilities in Amazon Ssm Agent
- 8.8 High severity
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 4.4 Medium severity
- 7.0 High severity
- 7.4 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
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