CVE-2012-3523
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe STARTTLS implementation in nnrpd in INN before 2.5.3 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe STARTTLS implementation in nnrpd (INN news server) before version 2.5.3 fails to properly flush or restrict I/O buffering during the TLS handshake transition. This allows a man-in-the-middle attacker to inject arbitrary NNTP commands into what should be an encrypted session by leveraging commands that remain in the buffer after TLS negotiation completes, similar to CVE-2011-0411 in Postfix.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 2.5.2= 1.4= 1.4sec= 1.4sec2= 1.4unoff3= 1.4unoff4= 1.5= 1.5.1= 1.7= 1.7.2= 2.0= 2.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify INN installationRun 'which inn' or 'which nnrpd' to confirm the INN news server binaries are present on the system. Also check for inn package via package manager (rpm -qa | grep inn or dpkg -l | grep inn).Affected if INN is not installed on the system.
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Determine installed INN versionRun 'innd -v' or 'nnrpd -v' to obtain the exact version number. Alternatively, query the package database: 'rpm -q inn' or 'dpkg -s inn'.Affected if The version is 2.5.2 or lower, or any of these versions: 1.4, 1.4sec, 1.4sec2, 1.4unoff3, 1.4unoff4, 1.5, 1.5.1, 1.7, 1.7.2, 2.0, 2.1.
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Confirm STARTTLS is enabledExamine the INN configuration file (typically /etc/inn/inn.conf or /etc/news/inn.conf) and look for 'tls' or 'starttls' directives. Also check reader.conf for nnrpd-specific TLS settings. Search for 'tls' or 'TLs' keywords in the configuration.Affected if STARTTLS support is explicitly enabled in the configuration files.
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Verify nnrpd is the active news readerCheck if nnrpd is running as the NNTP reader daemon: run 'ps aux | grep nnrpd' or check process list. Confirm that nnrpd handles NNTP connections for clients.Affected if nnrpd is the active NNTP reader daemon processing client connections.
The system is affected if INN version is 2.5.2 or earlier (including all listed 1.x and 2.x versions) and STARTTLS is enabled in the configuration, allowing nnrpd to accept encrypted connections that could be exploited by MITM injection.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade INN to version 2.5.3 or later which contains the corrected STARTTLS buffer handling. If immediate patching is not possible, consider restricting NNTP to local networks or enforcing IP-based access controls to reduce MITM exposure.
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-3523 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2012-3523 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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