Code execution via zero-length DDNS PACK entry
Published Oct 12, 2023 · Updated Aug 2, 2024
Heap-based buffer overflow in SoftEther VPN 4.41-9782-beta, 5.01.9674, and 5.02 allows man-in-the-middle attackers to execute code. WpcParsePacket treats a zero-length PACK entry as a NUL-terminated Base64 string, then decodes attacker-controlled bytes into a fixed 4,096-byte heap allocation. Exploitation requires control of the server's DDNS HTTP response path; a demonstrated payload crashes the VPN service, while code execution remains theoretical.
Summary
What happened
Heap-based buffer overflow in SoftEther VPN 4.41-9782-beta, 5.01.9674, and 5.02 allows man-in-the-middle attackers to execute code. WpcParsePacket treats a zero-length PACK entry as a NUL-terminated Base64 string, then decodes attacker-controlled bytes into a fixed 4,096-byte heap allocation. Exploitation requires control of the server's DDNS HTTP response path; a demonstrated payload crashes the VPN service, while code execution remains theoretical.
The record
- CVE
- CVE-2023-27395
- Published
- Oct 12, 2023
- Updated
- Aug 2, 2024
- Vendor
- SoftEther VPN Project
- Product
- SoftEther VPN
- Classifications
- CWE-122, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 12, 2023CVE publishedPublication date reported by the CVE source.
- Aug 2, 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=4.41-9782-beta
- Affected versionversion=5.01.9674
- Affected versionversion=5.02
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
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Cisco Talos zero-length PACK crash reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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