Storm in a teacup: Linux Command-Line Editors Do What they’re supposed to do, are called Vulnerable to High-Severity Bugs by ‘researcher’

A bug impacting editors Vim and Neovim could allow a trojan code to escape sandbox mitigations.

A high-severity bug impacting two popular command-line text editing applications, Vim and Neovim, allow remote attackers to execute arbitrary OS commands. Security researcher Armin Razmjou warned that exploiting the bug is as easy as tricking a target into clicking on a specially crafted text file in either editor.

Razmjou’s PoC is able to bypass modeline mitigations, which execute value expressions in a sandbox. That’s to prevent somebody from creating a trojan horse text file in modelines, the researcher said.

“However, the :source! command (with the bang [!] modifier) can be used to bypass the sandbox. It reads and executes commands from a given file as if typed manually, running them after the sandbox has been left,” according to the PoC report.

Vim and Neovim have both released patches for the bug (CVE-2019-12735) that the National Institute of Standards and Technology warns, “allows remote attackers to execute arbitrary OS commands via the :source! command in a modeline.”

“Beyond patching, it’s recommended to disable modelines in the vimrc (set nomodeline), to use the securemodelinesplugin, or to disable modelineexpr (since patch 8.1.1366, Vim-only) to disallow expressions in modelines,” the researcher said.

Source: Linux Command-Line Editors Vulnerable to High-Severity Bug | Threatpost

First off, you can’t click in vi, but OK. Second, the whole idea is that you can run commands from vi. So basically he is calling a functionality a flaw.

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