Debian LinuxOperating system · Debian
CVE-2016-7073
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 · uneditedAn issue has been found in PowerDNS before 3.4.11 and 4.0.2, and PowerDNS recursor before 4.0.4, allowing an attacker in position of man-in-the-middle to alter the content of an AXFR because of insufficient validation of TSIG signatures. A missing check of the TSIG time and fudge values was found in AXFRRetriever, leading to a possible replay attack.
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 confidencePowerDNS AXFRRetriever fails to validate TSIG time and fudge values, allowing a man-in-the-middle attacker to capture and replay valid AXFR responses to alter DNS zone transfer content. This is a replay attack vulnerability in the TSIG signature validation logic.
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
Debian LinuxOperating system
= 8.0< 3.4.11>= 4.0.0, < 4.0.2< 3.7.4>= 4.0.0, < 4.0.4CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
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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Check PowerDNS Authoritative Server versionRun 'pdns_server --version' or 'dnsdist --version' or check package manager (dpkg -l | grep pdns)Affected if Version is < 3.4.11, or >= 4.0.0 and < 4.0.2
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Check PowerDNS Recursor versionRun 'pdns_recursor --version' or check package manager (dpkg -l | grep pdns-recursor)Affected if Version is < 3.7.4, or >= 4.0.0 and < 4.0.4
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Identify if TSIG is configured for zone transfersCheck PowerDNS configuration for tsig-key definition in pdns.conf or check for tsig-at-zone-xfr parameter, and review AXFR settings in zone configurationAffected if TSIG keys are defined and used for AXFR zone transfers (the vulnerability only applies when TSIG is in use)
You are affected if PowerDNS Authoritative Server version is < 3.4.11 or between 4.0.0-4.0.2, OR Recursor version is < 3.7.4 or between 4.0.0-4.0.4, AND TSIG is configured for DNS zone transfers.
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 data3.4.113.7.44.0.2
Upgrade PowerDNS to version 3.4.11+, 4.0.2+, or recursor 4.0.4+ to include proper TSIG time/fudge validation. Additionally, use network segmentation to reduce man-in-the-middle attack surface on DNS infrastructure.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-7073 — 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-2016-7073 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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