Local directory deletion via directory junction
Published Mar 29, 2021 · Updated Aug 3, 2024
Improper link resolution in Avast Premium Security 20.8.2429 (Build 20.8.5653.561) allows local users to delete arbitrary directories. The AvastSvc.exe service follows an attacker-created directory junction and performs deletion on the linked path instead of constraining access to the intended directory. Exploitation requires low-privileged code execution on the Windows host and can interrupt service availability by deleting system or application directories.
Summary
What happened
Improper link resolution in Avast Premium Security 20.8.2429 (Build 20.8.5653.561) allows local users to delete arbitrary directories. The AvastSvc.exe service follows an attacker-created directory junction and performs deletion on the linked path instead of constraining access to the intended directory. Exploitation requires low-privileged code execution on the Windows host and can interrupt service availability by deleting system or application directories.
The record
- CVE
- CVE-2021-27241
- Published
- Mar 29, 2021
- Updated
- Aug 3, 2024
- Vendor
- Avast
- Product
- Avast Premium Security
- Classifications
- CWE-59, T1070.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 29, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record 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=20.8.2429 (Build 20.8.5653.561)
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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