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BindApplication · Isc

CVE-2009-0025

MEDIUM · 6.8 CVSS v2.0 Published 2009-01-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
BIND 9.6.0, 9.5.1, 9.5.0, 9.4.3, and earlier does not properly check the return value from the OpenSSL DSA_verify function, which allows remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature, a similar vulnerability to CVE-2008-5077.

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 confidence

BIND 9 versions 9.6.0, 9.5.1, 9.5.0, 9.4.3, and earlier fail to properly validate the return value from OpenSSL's DSA_verify function during SSL/TLS certificate chain verification, allowing remote attackers to bypass validation using malformed signatures.

MitigationUpgrade BIND 9 to a patched version (9.7.0 or later) that properly checks DSA_verify return values, and ensure OpenSSL is also updated to a version that addresses similar vulnerabilities.

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
BindApplication
Affected:= 9.0= 9.0.0= 9.0.1= 9.1= 9.1.0= 9.1.1= 9.1.2= 9.1.3= 9.2.0= 9.2.1= 9.2.2= 9.2.3

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify BIND 9 is installed
    Run 'named -v' or 'named -V' to display the BIND version, or check your package manager for the installed bind package.
    Affected if BIND 9 is installed with a version matching 9.0 through 9.2.3, or 9.4.3, 9.5.0, 9.5.1, or 9.6.0 (the vulnerable versions).
  2. Confirm the exact BIND version
    Compare the installed version output from 'named -v' against the affected range: 9.0, 9.0.0-9.0.1, 9.1.0-9.1.3, 9.2.0-9.2.3, 9.4.3, 9.5.0-9.5.1, and 9.6.0.
    Affected if The installed version falls within any of the listed vulnerable versions.
  3. Determine if SSL/TLS verification is in use
    Inspect BIND configuration files (named.conf) for directives enabling TLS, such as 'dnssec-validation', 'tls' sections, or queries over TLS (DoT). Also check if BIND is validating certificate chains for any secure connections.
    Affected if BIND is configured to perform SSL/TLS certificate chain verification, which is required to trigger the vulnerability.
  4. Check OpenSSL version used by BIND
    Run 'openssl version' to determine the OpenSSL library version, as the vulnerability involves DSA_verify return value checking in the OpenSSL interaction.
    Affected if OpenSSL is also vulnerable to similar signature validation issues, compounding the risk.

You are affected if BIND 9 is installed with a vulnerable version (9.0 through 9.2.3, 9.4.3, 9.5.0-9.5.1, or 9.6.0) AND BIND is configured to perform SSL/TLS certificate chain verification.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade BIND 9 to a patched version (9.7.0 or later) that properly checks DSA_verify return values, and ensure OpenSSL is also updated to a version that addresses similar vulnerabilities.

Fix this in Bind Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2009-0025 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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