Kcron: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2022-24986 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Kcron from KDE, with a CVSS 3.1 base score of 7.8 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. Affected Kcron versions: 21.12.2 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 0.25% 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 Kcron you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
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
- LowNo special conditions are needed; the attack works reliably.
- 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 2.0 | 4.6 | Medium | NVD |
Official description
KDE KCron through 21.12.2 uses a temporary file in /tmp when saving, but reuses the filename during an editing session. Thus, someone watching it be created the first time could potentially intercept the file the following time, enabling that person to run unauthorized commands.
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
Third-party and government advisories
- openwall.com/lists/oss-security/2022/02/25/3Mailing List, Third Party Advisory
Other references
- apps.kde.org/kcron/Product
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 8.1 High severity
- 7.0 High severity
- 6.4 Medium severity
Android Kernel Race Condition Exploited
- 6.4 Medium severity
Samsung Mobile Devices Race Condition Exploited
- 6.4 Medium severity
Samsung Mobile Devices Race Condition Exploited
- 8.8 High severity
Google Chromium Race Condition Exploited
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