Client session termination via cached pre-TLS option
Published Mar 2, 2022 · Updated Aug 3, 2024
Message-integrity failure in nbdkit 1.12 through 1.26.4 allows man-in-the-middle attackers to terminate an NBD client session. The newstyle handshake caches an injected plaintext NBD_OPT_STRUCTURED_REPLY across STARTTLS, causing later reads to receive unexpected structured replies. Exploitation requires opportunistic TLS, an on-path attacker, and a client that does not understand structured replies; the consequence is loss of the affected NBD session.
Summary
What happened
Message-integrity failure in nbdkit 1.12 through 1.26.4 allows man-in-the-middle attackers to terminate an NBD client session. The newstyle handshake caches an injected plaintext NBD_OPT_STRUCTURED_REPLY across STARTTLS, causing later reads to receive unexpected structured replies. Exploitation requires opportunistic TLS, an on-path attacker, and a client that does not understand structured replies; the consequence is loss of the affected NBD session.
The record
- CVE
- CVE-2021-3716
- Published
- Mar 2, 2022
- Updated
- Aug 3, 2024
- Vendor
- 389 Directory Server
- Product
- nbdkit
- Classifications
- CWE-924, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 2, 2022CVE 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=Affects nbdkit v1.12 through v1.26.4 | Fixedin nbdkit v1.26.5
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.
Weakness, pattern, technique
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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