{"investigation":{"slug":"coldcard-hardware-wallet-firmware-seed-entropy-exploit","entity_name":"Coldcard Hardware Wallet Firmware Seed Entropy Exploit","trust_score":8,"severity_base":null,"score_modifier":0,"confidence":0.85,"status":"draft","content_type":"investigation","summary":"A build-configuration error introduced into Coldcard hardware wallet firmware (made by Toronto-based Coinkite) in March 2021 caused affected devices to generate wallet seeds using a weak, deterministic software pseudorandom number generator instead of dedicated hardware entropy sources. Beginning July 30, 2026, attackers exploited the flaw to brute-force and sweep an estimated 1,816+ BTC (~$116 million) from more than 5,200 addresses across four waves, in what researchers describe as the largest hardware wallet exploit on record. Bitcoin developer James O'Beirne says he flagged the underlying randomness defect to Coinkite roughly 14 months earlier, in May 2025, and was told the problem would likely already have surfaced if it were real; he later published cryptographic evidence tying the vulnerable code's pseudonymous author to Coinkite co-founder and CTO Peter Gray.","sections":[{"content":"Coldcard firmware version 4.0.0/4.0.1, released in March 2021, introduced a new cryptographic library called libngu. A build configuration error meant that although Coldcard's production hardware disabled MicroPython's built-in hardware RNG (via the flag MICROPY_HW_ENABLE_RNG=0) in favor of a custom hardware-RNG wrapper, libngu incorrectly checked whether that macro was merely defined rather than whether it was enabled (nonzero). As a result, the build silently fell back to MicroPython's deterministic 'Yasmarang' software pseudorandom generator, seeded from the device's fixed MCU UID and timer/RTC registers, rather than true hardware entropy, according to a technical writeup published by Block's engineering team. On Mk2/Mk3 devices running firmware 4.0.0 through 4.1.9, this collapsed effective seed entropy to roughly 40 bits — far below the 128 bits expected for a standard 12-word BIP-39 seed — making seeds practically brute-forceable offline without physical access to the device. Mk4, Mk5, and Q devices were less severely but still meaningfully affected, retaining only a 32-bit secure-element reseed and roughly 72 bits of effective entropy rather than the intended 128, according to Coinkite's own advisory and Block's analysis. The source code was publicly available throughout this period and the correct hardware generator was present in the finished firmware, but reviewers reportedly confirmed the component's existence without tracing the full seed-generation call path, allowing the defect to go undetected for over five years, per CoinDesk's reporting.","heading":"The Vulnerability: Weak Seed Entropy in Coldcard Firmware","sources":[{"url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware","name":"Predictable RNG Fallback and 32-Bit Reseed in COLDCARD Firmware — Block Engineering Blog","type":"research","credibility":1},{"url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/","name":"Coldcard Security Advisory — Coinkite Blog","type":"official","credibility":1},{"url":"https://www.coindesk.com/tech/2026/08/17/how-a-bug-in-coldcard-s-code-went-unnoticed-for-years-leading-to-usd100-million-in-hacked-funds","name":"How a bug in Coldcard's code went unnoticed for years, leading to $100 million in hacked funds — CoinDesk","type":"news_article","credibility":2}],"severity":"critical"},{"content":"Beginning July 30, 2026, attackers began systematically sweeping bitcoin from addresses whose seeds had been generated on vulnerable Coldcard firmware. According to Galaxy Research's running tally cited by TRM Labs, roughly 1,816 BTC (approximately $116 million at the time) was drained from more than 5,200 addresses across four coordinated waves over the following days. Reported per-wave figures vary somewhat between outlets as the incident was tracked in near-real time (e.g., The Hacker News reported an initial wave draining roughly 1,083 BTC/$70.2 million from 1,196 addresses in 41 minutes, followed by further waves bringing the cumulative total to 1,816 BTC), but the aggregate scale — over 5,200 addresses and roughly $116 million — is consistently corroborated across TRM Labs, TechCrunch, Fortune, and The Hacker News. TRM Labs characterized laundering activity following the theft as comparatively modest and 'more exploratory' than patterns typical of state-linked actors such as North Korea's TraderTraitor group, noting only isolated laundering movements (including one identified Wasabi Wallet deposit and a Tornado Cash transfer) as of early August 2026. Multiple independent transaction-construction patterns across the waves suggest more than one attacker or group may have been involved; as of the most recent reporting, no specific threat actor had been publicly attributed. TechCrunch reported that security researchers believed at least a dozen different actors may have independently exploited the same flaw.","heading":"The Exploit: Four Waves, $116 Million Drained","sources":[{"url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack","name":"The Largest Hardware Wallet Exploit of 2026: Inside the USD 116 Million Coldcard Hack — TRM Labs","type":"research","credibility":1},{"url":"https://techcrunch.com/2026/08/04/hackers-steal-over-130-million-by-exploiting-bug-in-offline-hardware-wallets/","name":"Hackers steal over $130M by exploiting bug in offline hardware wallets — TechCrunch","type":"news_article","credibility":1},{"url":"https://thehackernews.com/2026/08/coldcard-hardware-wallet-flaw-linked-to.html","name":"Coldcard Hardware Wallet Flaw Linked to $70 Million Bitcoin Theft in 41 Minutes — The Hacker News","type":"news_article","credibility":2},{"url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/","name":"Bitcoin owners rocked by $116 million hack: What we know about the Coldcard exploit — Fortune","type":"news_article","credibility":1}],"severity":"critical"},{"content":"Bitcoin Core developer James O'Beirne — a long-tenured Bitcoin Core contributor known for the OP_VAULT (BIP-345) proposal and his role in the AssumeUTXO project, and a founding board member of OpenSats — has stated that he identified and raised concerns about the flawed randomness code in Coldcard's libngu library while conducting an audit in May 2025, roughly 14 months before the exploit became public. According to O'Beirne's account, he flagged the library as suspicious and recommended it be removed, but Coinkite's response was that a genuine problem would likely have already surfaced if the issue were real, and the warning was not acted upon. This account of the warning and its dismissal comes from O'Beirne himself, via social media posts and subsequent interviews reported by CoinDesk and other outlets; Coinkite has not, per available reporting, issued a detailed public rebuttal of O'Beirne's specific timeline or characterization of the exchange. This section should be read as an allegation from a single, credible but interested source (the person who says he issued the warning), corroborated only by secondary reporting rather than by a leaked or published copy of the original 2025 communication.","heading":"Prior Warning: James O'Beirne's May 2025 Disclosure","sources":[{"url":"https://www.coindesk.com/tech/2026/08/17/how-a-bug-in-coldcard-s-code-went-unnoticed-for-years-leading-to-usd100-million-in-hacked-funds","name":"How a bug in Coldcard's code went unnoticed for years, leading to $100 million in hacked funds — CoinDesk","type":"news_article","credibility":2},{"url":"https://phemex.com/academy/coldcard-security-flaw-warning","name":"Coinkite Was Warned 14 Months Early About the Coldcard Flaw — Phemex Academy","type":"news_article","credibility":2}],"severity":"critical"},{"content":"Following the exploit, James O'Beirne published an analysis alleging that the pseudonymous GitHub/commit account 'Switch,' which authored the libngu library containing the flawed RNG logic, is in fact Coinkite co-founder and CTO Peter Gray. O'Beirne's analysis rests on cryptographic evidence: he reported that 58 commits authored under the 'Switch' identity carried valid GPG signatures matching the same personal key Gray uses for commits made under his real name elsewhere in Coinkite's repositories. If accurate, this would mean the engineer who wrote the defective code and the executive who, per O'Beirne, dismissed his May 2025 warning about it, are the same person. This claim is alleged and based on O'Beirne's independent cryptographic analysis as reported by multiple crypto-news outlets (Cryptopolitan, CryptoTimes, Gate News, Cryptonews.net); it has not been independently verified by AVOID.NET, and available reporting indicates Coinkite has not issued a direct public response specifically addressing the identity claim, beyond general user-safety advisories.","heading":"Alleged Identity Link: Coinkite CTO Peter Gray and the Vulnerable Code","sources":[{"url":"https://www.cryptopolitan.com/coinkite-cto-peter-gray-linked-coldcard-hack/","name":"Coinkite CTO Peter Gray linked to the code behind the $114M Coldcard hack — Cryptopolitan","type":"news_article","credibility":2},{"url":"https://www.cryptotimes.io/2026/08/09/from-trusted-vendor-to-insider-job-coinkite-cto-now-linked-to-110m-coldcard-hack-code/","name":"From Trusted Vendor to Insider Job? Coinkite CTO Now Linked to $110M Coldcard Hack Code — Crypto Times","type":"news_article","credibility":2}],"severity":"high"},{"content":"Coinkite published a security advisory (initially dated around July 30, 2026 and updated August 1, 2026) confirming that Mk2/Mk3 firmware versions 4.0.1 through 4.1.9, and pre-patch versions of Mk4, Mk5, and Q firmware, were affected. The company released patched firmware (Mk4/Mk5 standard 5.6.0 or Edge 6.6.0X; Q standard 1.5.0Q or Edge 6.6.0QX) and stated that anyone who generated a seed on an affected device between March 2021 and the patch date should treat that seed as permanently compromised, regardless of whether the device has since been updated — updating firmware does not retroactively repair a seed generated under the flawed process. Coinkite advised affected users to generate an entirely new seed on updated firmware, verify the new wallet's fingerprint and a receive address, and migrate funds starting with a small test transaction. Coinkite acknowledged the severity of the incident publicly, stating 'the last three days have been some of the hardest in this company's history, and for a lot of the people reading this, they've been something much worse,' as reported by The Hacker News. One partial mitigation Coinkite identified: users who supplemented on-device generation with 50 or more independent physical dice rolls during seed creation are not considered at risk from this specific flaw, since the dice-derived entropy was combined independently of the broken RNG path.","heading":"Coinkite's Response and Remediation Guidance","sources":[{"url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/","name":"Coldcard Security Advisory — Coinkite Blog","type":"official","credibility":1},{"url":"https://thehackernews.com/2026/08/coldcard-hardware-wallet-flaw-linked-to.html","name":"Coldcard Hardware Wallet Flaw Linked to $70 Million Bitcoin Theft in 41 Minutes — The Hacker News","type":"news_article","credibility":2}],"severity":"high"},{"content":"This is not reported to be Coinkite's first friction with outside security researchers. According to a WebSearch-sourced summary of industry reporting, in August 2020 researchers from Shift Crypto and Nunchuk disclosed a multisig-verification flaw in Coldcard; Coinkite acknowledged the bug and shipped a fix, but its CEO reportedly characterized the disclosure itself as 'PR terrorism.' This 2020 episode is referenced in secondary industry commentary (including a CoinDesk opinion piece framed around the 2026 incident) as part of a broader narrative about Coinkite's historical posture toward external security criticism, though AVOID.NET was not able to directly access and quote primary source material for the 2020 dispute during this investigation; it should be treated as a lower-confidence, contextual claim pending direct sourcing.","heading":"Pattern of Prior Security-Disclosure Friction","sources":[{"url":"https://www.coindesk.com/opinion/2026/08/17/the-coldcard-hack-proves-reputation-is-not-a-security-model","name":"The Coldcard hack proves reputation is not a security model — CoinDesk (Opinion)","type":"news_article","credibility":2}],"severity":"medium"},{"content":"Following the exploit, victims began organizing toward potential class-action litigation against Coinkite. Thomas Braziel, founder and managing partner of 117 Partners, has been reported as coordinating an information-gathering effort among affected users across multiple countries, with product liability and negligence theories under consideration. As of the most recent available reporting, no class action had been formally filed; the effort remained in a pre-litigation, information-gathering phase. Legal commentators cited in press coverage are described as divided on Coinkite's ultimate liability, with some arguing the company bears limited direct responsibility for third-party criminal exploitation of a software defect, and others suggesting a credible basis exists to investigate design-defect and negligence claims, particularly in light of the alleged prior warning from James O'Beirne. This section describes an alleged, unresolved, and evolving legal situation; no adjudicated finding of liability exists as of this writing.","heading":"Legal Exposure and Class-Action Threat","sources":[{"url":"https://news.bitcoin.com/regulation-and-legal/coinkite-faces-class-action-threat-as-bitcoin-wallet-bug-costs-users-over-1300-btc/","name":"Coinkite Faces Class Action Threat as Bitcoin Wallet Bug Costs Users Over 1,300 BTC — Bitcoin.com News","type":"news_article","credibility":2},{"url":"https://www.cointribune.com/en/a-class-action-is-looming-against-coinkite-after-the-coldcard-wallets-hacking/","name":"A class action is looming against Coinkite after the COLDCARD wallets hacking — Cointribune","type":"news_article","credibility":2}],"severity":"high"}],"timeline":[{"date":"2021-03-17","event":"Coldcard firmware version 4.0.0, containing the defective libngu RNG-fallback logic, is released, beginning the period during which affected devices generated seeds with critically weakened entropy.","source":"Block Engineering Blog","source_url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware","date_evidence":"March 17, 2021: Firmware v4.0.0 released with vulnerable path"},{"date":"2025-05","event":"Bitcoin developer James O'Beirne says he identified the flawed randomness code in Coldcard's libngu library during an audit and warned Coinkite; he states the company dismissed the concern, saying a genuine problem would likely have already surfaced.","source":"CoinDesk","source_url":"https://www.coindesk.com/tech/2026/08/17/how-a-bug-in-coldcard-s-code-went-unnoticed-for-years-leading-to-usd100-million-in-hacked-funds"},{"date":"2026-07-30","event":"Attackers begin sweeping bitcoin from Coldcard-generated addresses in the first of four coordinated waves, exploiting the weak-entropy seed vulnerability.","source":"TRM Labs","source_url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack","date_evidence":"Starting July 30, 2026, attackers drained roughly 1,816 BTC (~$116 million) from over 5,200 addresses across four waves"},{"date":"2026-07","event":"Coinkite publishes an initial security advisory regarding the Coldcard seed-generation vulnerability.","source":"Coinkite Blog","source_url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/","date_original":"2026-07-30"},{"date":"2026-08-01","event":"Coinkite updates its public security advisory with additional detail on affected firmware versions and remediation steps.","source":"Coinkite Blog","source_url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/","date_evidence":"Advisory Update: August 1, 2026 at 2:35 p.m. EDT"},{"date":"2026-08-04","event":"Cumulative reported losses reach over $130 million (subsequently converging on a widely cited total of roughly 1,816 BTC / $116 million) from more than 5,200 addresses across four waves; TechCrunch and other outlets report Coinkite has not provided detailed comment.","source":"TechCrunch","source_url":"https://techcrunch.com/2026/08/04/hackers-steal-over-130-million-by-exploiting-bug-in-offline-hardware-wallets/","date_evidence":"Over $130 million as of Tuesday, August 4, 2026, according to Galaxy Research and Elliptic estimates"},{"date":"2026-08","event":"James O'Beirne publishes cryptographic analysis alleging that the pseudonymous author of the vulnerable libngu code, known as 'Switch,' is Coinkite co-founder and CTO Peter Gray, based on matching GPG commit signatures.","source":"Cryptopolitan","source_url":"https://www.cryptopolitan.com/coinkite-cto-peter-gray-linked-coldcard-hack/"},{"date":"2026-08-17","event":"CoinDesk publishes retrospective reporting and opinion analysis on how the bug went unnoticed for years and what it reveals about reputation-based trust in hardware wallet security.","source":"CoinDesk","source_url":"https://www.coindesk.com/tech/2026/08/17/how-a-bug-in-coldcard-s-code-went-unnoticed-for-years-leading-to-usd100-million-in-hacked-funds","date_evidence":"coindesk.com/opinion/2026/08/17/the-coldcard-hack-proves-reputation-is-not-a-security-model"},{"date":"2026-08","event":"Victims begin organizing toward a potential class-action lawsuit against Coinkite, coordinated in part by 117 Partners; no lawsuit has been formally filed as of the most recent available reporting.","source":"Cointribune","source_url":"https://www.cointribune.com/en/a-class-action-is-looming-against-coinkite-after-the-coldcard-wallets-hacking/"}],"sources_used":[{"url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack","name":"The Largest Hardware Wallet Exploit of 2026: Inside the USD 116 Million Coldcard Hack — TRM Labs","type":"research","archive_url":"http://web.archive.org/web/20260921141512/https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack","credibility":1,"archive_timestamp":"2026-09-21T14:15:12+00:00"},{"url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/","name":"Coldcard Security Advisory — Coinkite Blog","type":"official","archive_url":"http://web.archive.org/web/20260921143236/https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/","credibility":1,"archive_timestamp":"2026-09-21T14:32:36+00:00"},{"url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware","name":"Predictable RNG Fallback and 32-Bit Reseed in COLDCARD Firmware — Block Engineering Blog","type":"research","archive_url":"http://web.archive.org/web/20260911040619/https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware","credibility":1,"archive_timestamp":"2026-09-11T04:06:19+00:00"},{"url":"https://techcrunch.com/2026/08/04/hackers-steal-over-130-million-by-exploiting-bug-in-offline-hardware-wallets/","name":"Hackers steal over $130M by exploiting bug in offline hardware wallets — TechCrunch","type":"news_article","archive_url":"http://web.archive.org/web/20260921093735/https://techcrunch.com/2026/08/04/hackers-steal-over-130-million-by-exploiting-bug-in-offline-hardware-wallets/","credibility":1,"archive_timestamp":"2026-09-21T09:37:35+00:00"},{"url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/","name":"Bitcoin owners rocked by $116 million hack: What we know about the Coldcard exploit — Fortune","type":"news_article","archive_url":"http://web.archive.org/web/20260921122358/https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/","credibility":1,"archive_timestamp":"2026-09-21T12:23:58+00:00"},{"url":"https://thehackernews.com/2026/08/coldcard-hardware-wallet-flaw-linked-to.html","name":"Coldcard Hardware Wallet Flaw Linked to $70 Million Bitcoin Theft in 41 Minutes — The Hacker News","type":"news_article","archive_url":"http://web.archive.org/web/20260921092352/https://thehackernews.com/2026/08/coldcard-hardware-wallet-flaw-linked-to.html","credibility":2,"archive_timestamp":"2026-09-21T09:23:52+00:00"},{"url":"https://www.coindesk.com/tech/2026/08/17/how-a-bug-in-coldcard-s-code-went-unnoticed-for-years-leading-to-usd100-million-in-hacked-funds","name":"How a bug in Coldcard's code went unnoticed for years, leading to $100 million in hacked funds — CoinDesk","type":"news_article","archive_url":"http://web.archive.org/web/20260818105755/https://www.coindesk.com/tech/2026/08/17/how-a-bug-in-coldcard-s-code-went-unnoticed-for-years-leading-to-usd100-million-in-hacked-funds","credibility":2,"archive_timestamp":"2026-08-18T10:57:55+00:00"},{"url":"https://www.coindesk.com/opinion/2026/08/17/the-coldcard-hack-proves-reputation-is-not-a-security-model","name":"The Coldcard hack proves reputation is not a security model — CoinDesk (Opinion)","type":"news_article","archive_url":"http://web.archive.org/web/20260917160329/https://www.coindesk.com/opinion/2026/08/17/the-coldcard-hack-proves-reputation-is-not-a-security-model","credibility":2,"archive_timestamp":"2026-09-17T16:03:29+00:00"},{"url":"https://phemex.com/academy/coldcard-security-flaw-warning","name":"Coinkite Was Warned 14 Months Early About the Coldcard Flaw — Phemex Academy","type":"news_article","archive_url":"http://web.archive.org/web/20260921120545/https://phemex.com/academy/coldcard-security-flaw-warning","credibility":2,"archive_timestamp":"2026-09-21T12:05:45+00:00"},{"url":"https://www.cryptopolitan.com/coinkite-cto-peter-gray-linked-coldcard-hack/","name":"Coinkite CTO Peter Gray linked to the code behind the $114M Coldcard hack — Cryptopolitan","type":"news_article","archive_url":"http://web.archive.org/web/20260921110514/https://www.cryptopolitan.com/coinkite-cto-peter-gray-linked-coldcard-hack/","credibility":2,"archive_timestamp":"2026-09-21T11:05:14+00:00"},{"url":"https://www.cryptotimes.io/2026/08/09/from-trusted-vendor-to-insider-job-coinkite-cto-now-linked-to-110m-coldcard-hack-code/","name":"From Trusted Vendor to Insider Job? Coinkite CTO Now Linked to $110M Coldcard Hack Code — Crypto Times","type":"news_article","archive_url":"http://web.archive.org/web/20260809055901/https://www.cryptotimes.io/2026/08/09/from-trusted-vendor-to-insider-job-coinkite-cto-now-linked-to-110m-coldcard-hack-code/","credibility":2,"archive_timestamp":"2026-08-09T05:59:01+00:00"},{"url":"https://news.bitcoin.com/regulation-and-legal/coinkite-faces-class-action-threat-as-bitcoin-wallet-bug-costs-users-over-1300-btc/","name":"Coinkite Faces Class Action Threat as Bitcoin Wallet Bug Costs Users Over 1,300 BTC — Bitcoin.com News","type":"news_article","archive_url":"http://web.archive.org/web/20260913234923/https://news.bitcoin.com/regulation-and-legal/coinkite-faces-class-action-threat-as-bitcoin-wallet-bug-costs-users-over-1300-btc/","credibility":2,"archive_timestamp":"2026-09-13T23:49:23+00:00"},{"url":"https://www.cointribune.com/en/a-class-action-is-looming-against-coinkite-after-the-coldcard-wallets-hacking/","name":"A class action is looming against Coinkite after the COLDCARD wallets hacking — Cointribune","type":"news_article","archive_url":"https://web.archive.org/web/20260922211223/https://www.cointribune.com/en/a-class-action-is-looming-against-coinkite-after-the-coldcard-wallets-hacking/","credibility":2,"archive_timestamp":"2026-09-22T21:12:23+00:00"}],"source_tags":[],"addresses":[],"reviewed":false,"reviewed_by":null,"model_used":"claude-code-investigator","created_at":"2026-09-22T17:05:14.167164+00:00","updated_at":"2026-09-22T21:21:15.496539+00:00"}}