http://bugzilla.opensuse.org/show_bug.cgi?id=1205305 Bug ID: 1205305 Summary: VUL-0: CVE-2022-45063: xterm: code execution via font ops Classification: openSUSE Product: openSUSE Distribution Version: Leap 15.4 Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Security Assignee: meissner@suse.com Reporter: Andreas.Stieger@gmx.de QA Contact: security-team@suse.de Found By: --- Blocker: --- It was reported that xterm before patch 375 can enable an RCE under certain conditions. The issue is in the OSC 50 sequence, which is for setting and querying the font. If a given font does not exist, it is not set, but a query will return the name that was set. Control characters can't be included, but the response string can be terminated with ^G. This essentially gives us a primitive for echoing text back to the terminal and ending it with ^G. It so happens ^G is in Zsh when in vi line editing mode bound to "list-expand". Which can run commands as part of the expansion leading to command execution without pressing enter! This does mean to exploit this vulnerability the user needs to be using Zsh in vi line editing mode (usually via $EDITOR having "vi" in it). While somewhat obscure this is not a totally unknown configuration. In that configuration, something like: printf "\e]50;i\$(touch /tmp/hack-like-its-1999)\a\e]50;?\a" > cve-2022-45063 cat cve-2022-45063 # or another way to deliver this to the victim Will touch that file. It will leave the line on the user's screen; I'll leave it as an exercise for the reader to use the vi line editing commands to hide the evidence. Mitigation: Set this Xresource: XTerm*allowFontOps: false References: https://www.openwall.com/lists/oss-security/2022/11/10/1 -- You are receiving this mail because: You are on the CC list for the bug.