Information disclosure via predictable TCP sequence numbers
Published Dec 25, 2021 · Updated Aug 4, 2024
Information disclosure in NetBSD 9.2 and earlier allows remote attackers to infer connection activity through crafted TCP exchanges. The TCP ISN generator forms its most significant eight bits by adding a 2 Hz timer to a global connection counter modulo 256, exposing counter changes. Exploitation requires coordinated sender and receiver traffic to a reachable TCP endpoint with low jitter; the leak supports host aliasing and a covert channel rather than direct data reads.
Summary
What happened
Information disclosure in NetBSD 9.2 and earlier allows remote attackers to infer connection activity through crafted TCP exchanges. The TCP ISN generator forms its most significant eight bits by adding a 2 Hz timer to a global connection counter modulo 256, exposing counter changes. Exploitation requires coordinated sender and receiver traffic to a reachable TCP endpoint with low jitter; the leak supports host aliasing and a covert channel rather than direct data reads.
The record
- CVE
- CVE-2021-45488
- Published
- Dec 25, 2021
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-330, T1048
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 25, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 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
- Subverting Stateful Firewalls with Protocol Statesproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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