Remote CPU exhaustion via unchecked length subtraction
Published Dec 22, 2023 · Updated Aug 2, 2024
Integer overflow in MatrixSSL 4.0.0 through 4.6.0 and Rambus TLS Toolkit allows remote attackers to exhaust server CPU via TLS messages. During TLS 1.3 Client Hello pre-shared-key parsing, tls13VerifyBinder subtracts an attacker-controlled binder length from the unsigned Client Hello length without checking for underflow, then passes the wrapped value to tls13TranscriptHashUpdate. Repeated unauthenticated connections make the server hash at least 65 KB of RAM per crafted message, heavily loading the CPU and interrupting service.
Summary
What happened
Integer overflow in MatrixSSL 4.0.0 through 4.6.0 and Rambus TLS Toolkit allows remote attackers to exhaust server CPU via TLS messages. During TLS 1.3 Client Hello pre-shared-key parsing, tls13VerifyBinder subtracts an attacker-controlled binder length from the unsigned Client Hello length without checking for underflow, then passes the wrapped value to tls13TranscriptHashUpdate. Repeated unauthenticated connections make the server hash at least 65 KB of RAM per crafted message, heavily loading the CPU and interrupting service.
The record
- CVE
- CVE-2023-24609
- Published
- Dec 22, 2023
- Updated
- Aug 2, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-190, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 22, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- Crafted TLS 1.3 Client Hello packetproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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