Unauthenticated file write via traversed upload path
Published Dec 8, 2021 · Updated Aug 3, 2024
Relative path traversal in affected SonicWall SMA 100 Series firmware allows remote attackers to write files outside the upload directory. The unauthenticated RAC_POST_FILE_LIST method builds a path from the swcctn query value without canonicalization or traversal checks, then passes it to Python file operations. Files receive timestamp-suffixed names and nobody-user permissions, allowing controlled content in writable web or configuration directories.
Summary
What happened
Relative path traversal in affected SonicWall SMA 100 Series firmware allows remote attackers to write files outside the upload directory. The unauthenticated RAC_POST_FILE_LIST method builds a path from the swcctn query value without canonicalization or traversal checks, then passes it to Python file operations. Files receive timestamp-suffixed names and nobody-user permissions, allowing controlled content in writable web or configuration directories.
The record
- CVE
- CVE-2021-20040
- Published
- Dec 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- SonicWall
- Product
- Secure Mobile Access (SMA) 100 Series
- Classifications
- CWE-22, CWE-23, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 8, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.2.0.8-37sv and earlier
- Affected versionversion=10.2.1.1-19sv and earlier
- Affected versionversion=10.2.1.2-24sv and earlier
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
- NCC Group unauthenticated file-upload path-traversal demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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