SYSTEM code execution via symlink TOCTTOU
Published May 9, 2025 · Updated May 9, 2025
Link following in TuneupSvc in Avast Cleanup Premium 24.2.16593.17810 allows local users to execute arbitrary code as SYSTEM. TuneupSvc checks a filesystem path and later uses it without preventing symbolic-link substitution during the intervening TOCTTOU window. A low-privileged Windows 10 Pro x64 user who wins the local race can redirect the privileged service's file access and run attacker-controlled code with SYSTEM privileges.
Summary
What happened
Link following in TuneupSvc in Avast Cleanup Premium 24.2.16593.17810 allows local users to execute arbitrary code as SYSTEM. TuneupSvc checks a filesystem path and later uses it without preventing symbolic-link substitution during the intervening TOCTTOU window. A low-privileged Windows 10 Pro x64 user who wins the local race can redirect the privileged service's file access and run attacker-controlled code with SYSTEM privileges.
The record
- CVE
- CVE-2024-13962
- Published
- May 9, 2025
- Updated
- May 9, 2025
- Vendor
- Avast
- Product
- Avast Cleanup Premium
- Classifications
- CWE-59, CAPEC-233, CAPEC-549, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 9, 2025CVE publishedPublication date reported by the CVE source.
- May 9, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=24.2.16593.17810
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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