Root-level file writes via traversal-assisted upload
Published Oct 13, 2021 · Updated Aug 3, 2024
Arbitrary file upload in DownloadFileServlet in DrayTek VigorConnect 1.6.0-B3 allows remote attackers to write files as root. The servlet accepts a multipart file and attacker-controlled path, resolves traversal segments without confining the destination, and writes the supplied bytes. Unauthenticated access to the management service is sufficient, and the resulting write can place attacker-controlled content anywhere permitted by the service's root privileges.
Summary
What happened
Arbitrary file upload in DownloadFileServlet in DrayTek VigorConnect 1.6.0-B3 allows remote attackers to write files as root. The servlet accepts a multipart file and attacker-controlled path, resolves traversal segments without confining the destination, and writes the supplied bytes. Unauthenticated access to the management service is sufficient, and the resulting write can place attacker-controlled content anywhere permitted by the service's root privileges.
The record
- CVE
- CVE-2021-20125
- Published
- Oct 13, 2021
- Updated
- Aug 3, 2024
- Vendor
- DrayTek
- Product
- VigorConnect
- Classifications
- CWE-22, CWE-434, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 13, 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=1.6.0-B3
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
- Tenable DownloadFileServlet upload proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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