CVE-2017-9230
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 Bitcoin Proof-of-Work algorithm does not consider a certain attack methodology related to 80-byte block headers with a variety of initial 64-byte chunks followed by the same 16-byte chunk, multiple candidate root values ending with the same 4 bytes, and calculations involving sqrt numbers. This violates the security assumptions of (1) the choice of input, outside of the dedicated nonce area, fed into the Proof-of-Work function should not change its difficulty to evaluate and (2) every Proof-of-Work function execution should be independent. NOTE: a number of persons feel that this methodology is a benign mining optimization, not a vulnerability
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 · moderate confidenceThis vulnerability in Bitcoin's PoW algorithm allows specially crafted 80-byte block headers to be evaluated with significantly reduced computational difficulty compared to standard inputs. Attackers can manipulate the initial 64-byte chunk followed by identical 16-byte chunks, combined with candidate roots ending in matching 4-byte suffixes and sqrt calculations, to create inputs that are faster to hash. This breaks the security assumption that non-nonce input choices should have uniform evaluation difficulty and that each PoW execution should be independent.
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 dataall versionsCVSS 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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 if Bitcoin software is runningCheck for running Bitcoin daemon processes using commands like 'ps aux | grep bitcoind' or 'systemctl status bitcoind'Affected if Bitcoin daemon (bitcoind) is actively running on the system
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Verify Bitcoin protocol implementationExamine the source code or binary to confirm it uses the original PoW algorithm with the vulnerable 80-byte block header processing that allows differential difficulty through sqrt-based calculationsAffected if The implementation uses the original Bitcoin PoW with the vulnerability present (affects all versions)
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Check block header processingInspect how the software processes 80-byte block headers, specifically looking for sqrt calculations and handling of 64-byte initial chunks with 16-byte repeating patterns in the PoW validationAffected if The PoW validation path processes headers using the vulnerable sqrt-based method that allows manipulated inputs to have reduced computational difficulty
If Bitcoin software using the original PoW algorithm is running and processes 80-byte block headers through the vulnerable sqrt-based evaluation method, the environment is affected by this protocol-level flaw that allows differential difficulty based on input structure.
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 dataRemediation would require a protocol-level change to Bitcoin's PoW function to prevent differential difficulty evaluation based on input structure. This typically involves modifying how block headers are processed to normalize computational load regardless of input format, though the decentralized nature of Bitcoin makes such changes extremely difficult to deploy.
- Consultation40.0 h
- Implementation80.0 h
- Testing60.0 h
- Review / QA40.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $61,760.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-9230 — 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-2017-9230 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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