Filter bypass via malformed encoded HTTP responses
Published Feb 16, 2023 · Updated Aug 3, 2024
Improper input validation in Cisco Secure Web Appliance allows remote attackers to bypass web-filter rules via malformed HTTP responses. Its AsyncOS scanning engines fail to detect malformed content-encoded traffic and therefore do not apply a configured explicit block rule. Exploitation requires no authentication but requires traffic through the appliance to an attacker-controlled server; the result is receipt of content the policy should reject.
Summary
What happened
Improper input validation in Cisco Secure Web Appliance allows remote attackers to bypass web-filter rules via malformed HTTP responses. Its AsyncOS scanning engines fail to detect malformed content-encoded traffic and therefore do not apply a configured explicit block rule. Exploitation requires no authentication but requires traffic through the appliance to an attacker-controlled server; the result is receipt of content the policy should reject.
The record
- CVE
- CVE-2022-20952
- Published
- Feb 16, 2023
- Updated
- Aug 3, 2024
- Vendor
- ClamAV
- Product
- Cisco Secure Web Appliance
- Classifications
- CWE-20
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 16, 2023CVE 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=11.8.0-414
- Affected versionversion=11.8.1-023
- Affected versionversion=11.8.3-018
- Affected versionversion=11.8.3-021
- Affected versionversion=12.0.1-268
- Affected versionversion=12.0.3-007
- Affected versionversion=12.5.1-011
- Affected versionversion=12.5.2-007
- Affected versionversion=12.5.4-005
- Affected versionversion=12.5.5-004
- Affected versionversion=14.0.2-012
- Affected versionversion=14.0.3-014
- Affected versionversion=14.5.0-498
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.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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