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CLI ambush#

hack.lu 2025 digest Program Adjacent pick 21–24 October 2025

Abstract Slides Recording

William Robinet

Play the recording: CLI ambush

  • Why: The TLS/SSL toolkits administrators run by hand are themselves an attack surface — crafted ASN.1 input trapping the operator is a novel trust-boundary problem at the CLI/PKI layer the PM cares about.
  • What: A vulnerability class common to various TLS/SSL cryptographic toolkits, triggered by crafted ASN.1 messages, demonstrated in the OpenSSL CLI and extended to other toolkits, with attack vectors that can trap unsuspecting administrators. (from abstract only)
  • How: Crafting ASN.1 messages that expose handling issues in CLI applications, then walking through the discovered attack vectors.
  • Where applicable: Any workflow where admins process untrusted cryptographic input (certificates, keys) via OpenSSL-like CLIs; general technique, toolkit-dependent.