Unauthenticated connection interruption via in-window TCP resets
Published Sep 29, 2025 · Updated Sep 29, 2025
Denial of service in Nanda Automation Technology AT_NA2000 allows remote attackers to interrupt PLC TCP connections with forged RST packets. Its TCP stack accepts an RST sequence number anywhere inside the current receive window instead of requiring the exact next expected value. Network access to a live TCP session is sufficient; repeated guesses spanning the receive window terminate the connection without authentication.
Summary
What happened
Denial of service in Nanda Automation Technology AT_NA2000 allows remote attackers to interrupt PLC TCP connections with forged RST packets. Its TCP stack accepts an RST sequence number anywhere inside the current receive window instead of requiring the exact next expected value. Network access to a live TCP session is sufficient; repeated guesses spanning the receive window terminate the connection without authentication.
The record
- CVE
- CVE-2025-56234
- Published
- Sep 29, 2025
- Updated
- Sep 29, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 29, 2025CVE publishedPublication date reported by the CVE source.
- Sep 29, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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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
- AT_NA2000 TCP RST proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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