Firewall-policy bypass via unauthenticated UDP notifications
Published Jul 12, 2021 · Updated Oct 25, 2024
Improper authentication in Fortinet FSSO Collector 5.0.295 and earlier allows remote attackers to bypass firewall policy via UDP. The Collector Agent accepts plaintext UDP login notifications on port 8002 without authenticating their sender, so crafted packets are treated as legitimate logon events. Access requires adjacent-network reachability to the UDP listener and grants protected-network access under a forged logon identity.
Summary
What happened
Improper authentication in Fortinet FSSO Collector 5.0.295 and earlier allows remote attackers to bypass firewall policy via UDP. The Collector Agent accepts plaintext UDP login notifications on port 8002 without authenticating their sender, so crafted packets are treated as legitimate logon events. Access requires adjacent-network reachability to the UDP listener and grants protected-network access under a forged logon identity.
The record
- CVE
- CVE-2021-26088
- Published
- Jul 12, 2021
- Updated
- Oct 25, 2024
- Vendor
- Fortinet
- Product
- Fortinet Single Sign-On (FSSO)
- Classifications
- CWE-287, T1210
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 12, 2021CVE publishedPublication date reported by the CVE source.
- Oct 25, 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=FSSO Windows DC Agent 5.0.295, 5.0.294; FSSO Windows CA 5.0.295, 5.0.294
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.
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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