Spenser Jones

Sudo bug lets non-privileged users run as root if pwfeedback is enabled

A new vulnerability in Sudo has been discovered, allowing non-privileged users to execute arbitrary commands as 'root' if the environment is configured with pwfeedback. This was discovered by Joe Vennix of Apple Information Security, who also discovered a potential bypass of Runas user restrictions in October of 2019, and has been assigned CVE-2019-18634. Most Linux distributions do not have pwfeedback enabled by default, however Linux Mint and Elementary OS do, and if enabled it will provide an asterisk (*) as a visual representation of the characters that have been entered, instead of the default of displaying nothing. This bug can be reproduced by passing a large input to sudo via a pipe, causing a buffer overfow and bypassing the authorization check.

This has been fixed in Sudo 1.8.31, as well as in macOS High Sierra 10.13.6, Mojave 10.14.6, Catalina 10.15.2.

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