Description
The Korn shell (aka mksh) before R33d on MirOS (aka MirBSD) does not flush the tty's I/O when invoking mksh in a new terminal, which allows local users to gain privileges by opening a virtual terminal and entering command sequences, which might later be executed in opportunistic circumstances by a different user who launches mksh and specifies that terminal with the -T option.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | mksh | 33.4-1 | — |
| Debian 13 | mksh | 33.4-1 | — |
| Debian 12 | mksh | 33.4-1 | — |
References
- 44365 vdb-entry
- 28768 vdb-entry
- 29803 third-party-advisory
- mirbsd-tty-privilege-escalation(41794) vdb-entry
- http://www.mirbsd.org/mksh.htm#clog