pam_usb: PINENTRY_FALLBACK_APP environment variable allows arbitrary command execution
pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.8.7, pamusb-pinentry reads the PINENTRY_FALLBACK_APP environment variable and executes it directly without any validation. Any process that can set environment variables before pamusb-pinentry is invoked can point PINENTRY_FALLBACK_APP at an arbitrary binary or script and have it executed with the privileges of the pam_usb tool chain. This vulnerability is fixed in 0.8.7.
AV:LAttack VectorAC:LAttack ComplexityPR:LPrivileges RequiredUI:NUser InteractionS:UScopeC:HConfidentialityI:HIntegrityA:HAvailabilityClick technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.
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