Debian LinuxOperating system · Debian
CVE-2016-7074
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 that the TSIG record is the last one, leading to the possibility of parsing records that are not covered by the TSIG signature.
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 fails to verify that the TSIG (Transaction Signature) record is the last record in an AXFR (zone transfer) response. This allows a man-in-the-middle attacker to append additional DNS records after the TSIG signature that are not validated by the signature, potentially altering zone transfer content.
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< 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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Identify PowerDNS product and versionRun 'pdns_control version' for Authoritative Server, or 'rec_control version' for Recursor. On Debian, also check 'dpkg -l | grep powerdns'.Affected if Installed version is < 3.4.11 or >= 4.0.0 AND < 4.0.2 for Authoritative Server, or < 4.0.4 for Recursor.
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Confirm AXFR zone transfer functionality is enabledCheck pdns.conf (typically /etc/pdns/pdns.conf) or recursor.conf for 'allow-axfr' or 'master'/'slave' directives. Run 'pdns_control list all' or review configuration files.Affected if The server is configured as a master or slave for DNS zone transfers, or 'allow-axfr' is set to allow any transfers.
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Verify TSIG is configured for zone transfersReview pdns.conf for 'tsig-key' entries or check if AXFR is configured with TSIG authentication. Look for 'allow-axfr' rules that reference tsig-key names.Affected if TSIG keys are defined and used to sign AXFR responses, making the server a target for this vulnerability.
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Check network exposure of AXFR serviceReview firewall rules and pdns.conf 'allow-axfr' settings to determine which IP addresses can request zone transfers. Inspect 'also-notify' and 'forward-zones' if configured.Affected if AXFR service is accessible from untrusted networks or IP addresses beyond the DNS operator's control.
You are affected if you run a vulnerable PowerDNS version (Auth < 3.4.11 or >= 4.0.0 & < 4.0.2, Recursor < 4.0.4) AND have AXFR with TSIG enabled and exposed to untrusted networks.
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 data3.4.114.0.24.0.4
Upgrade PowerDNS to version 3.4.11+, 4.0.2+, or PowerDNS Recursor to 4.0.4+. As a compensating control, restrict AXFR to trusted IP addresses at the network level.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-7074 — 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-2016-7074 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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