Researchers have uncovered vulnerabilities in the widely deployed Ghostscript package that allows bad actors to remotely take control of vulnerable systems. There's no current patch available for the multiple flaws discovered.
Ghostscript is a suite of tools used by hundreds of software suites and coding libraries, which allows desktop software and web servers to handle Adobe Systems' PostScript and PDF page description languages.
Multiple bypass vulnerabilities, disclosed Tuesday, exist in the suite's optional -dSAFER feature, which is ironically supposed to prevent unsafe PostScript operations. By causing Ghostscript (or a program leveraging Ghostscript) to parse a specially-crafted malicious file, a remote, unauthenticated attacker may be able to execute arbitrary commands with the privileges of the Ghostscript code.
(Score: 2, Informative) by Anonymous Coward on Thursday August 23 2018, @03:35PM
Typically gs would run at the privilege level of the user invoking the converter. So if you are logged in as root, well, that could then be a big problem.
But, gs is also invoked in a lot of other places. Like, i.e., as part of printing (i.e., cups).
And if cups is running as root, unless cups runs GS in a privilege reduced sandbox, then there's your vector to gaining root. Simply 'print' the malicious ps file as a normal user, and have it (the ps file) when it breaks out of gs make the necessary changes so you, normal user, gain a root shell.