Exploiting zero days in abandoned hardware

Alan Cao, Will Tan
We successfully exploited two discontinued network devices at DistrictCon’s inaugural Junkyard competition in February, winning runner-up for Most Innovative Exploitation Technique. Our exploit chains demonstrate why end-of-life hardware poses persistent security risks.

Detecting code copying at scale with Vendetect

Evan Sultanik
Vendetect is our new open-source tool for detecting copied and vendored code between repositories. It uses semantic fingerprinting to identify similar code even when variable names change or comments disappear. More importantly, unlike academic plagiarism detectors, it understands version control history, helping you trace vendored code back to its exact source commit.

Maturing your smart contracts beyond private key risk

Private key compromise accounted for 43.8% of crypto hacks in 2024, yet traditional smart contract audits rarely address architectural access control weaknesses. This post introduces a four-level maturity framework for designing protocols that can tolerate key compromise, progressing from single EOA control to radical immutability, with practical examples demonstrating multisigs, timelocks, and the principle of least privilege.

Unexpected security footguns in Go's parsers

File parsers in Go contain unexpected behaviors that can lead to serious security vulnerabilities. This post examines how JSON, XML, and YAML parsers in Go handle edge cases in ways that have repeatedly resulted in high-impact security issues in production systems. We explore three real-world attack scenarios: marshaling/unmarshaling unexpected data, exploiting parser differentials, and leveraging data format confusion. Through examples, we demonstrate how attackers can bypass authentication, circumvent authorization controls, and exfiltrate sensitive data by exploiting these parser behaviors.

What we learned reviewing one of the first DKLs23 libraries from Silence Laboratories

Joop van de Pol, Jim Miller, and Joe Doyle
In October 2023, we audited Silence Laboratories’ DKLs23 threshold signature scheme (TSS) library—one of the first production implementations of this then-novel protocol that uses oblivious transfer (OT) instead of traditional Paillier cryptography. Our review uncovered serious flaws that could enable key destruction attacks, which Silence Laboratories promptly fixed.

A deep dive into Axiom’s Halo2 circuits

Filipe Casal, Jim Miller, Fredrik Dahlgren, Joe Doyle, Tjaden Hess, Marc Ilunga
Over two audits in 2023, we reviewed a blockchain system developed by Axiom that allows computing over the entire history of Ethereum, all verified by zero-knowledge proofs (ZKPs) on-chain using ZK-verified elliptic curve and SNARK recursion operations. This system is built using the Halo2 framework—a complex, emerging technology that presents many challenges when building a secure application, including potential under-constrained issues resulting from its low-level API.

The cryptography behind passkeys

Joop van de Pol
This post will examine the cryptography behind passkeys, the guarantees they do or do not give, and interesting cryptographic things you can do with them, such as generating cryptographic keys and storing certificates.