Date: Thu, 18 Dec 2014 16:51:29 +0100 From: Dawa Ometto <d.l.a.ometto@...nl> To: <oss-security@...ts.openwall.com> Subject: Re: CVE request: remote code execution vulnerability in gollum < 3.1.1 Resubmitting this (while fixing version number typo in the subject-line) since it never did receive a CVE. On 04/12/14 22:08, Dawa Ometto wrote: > Hi, > > I just released a fix for a remote code execution vulnerability in > gollum . The vulnerable code was in the gollum-grit_adapter  ruby > gem dependency as of gollum v3.1.0, but the exploitable code was also > present before that version, in the gollum-lib  gem dependency (code > was abstracted from gollum-lib to the new dependency). > > Type of vulnerability: remote code execution > Attack outcome: run arbitrary commands, shell access > Vulnerable versions: gollum < 3.1.1, gollum-lib < 4.0.1, > gollum-grit_adapter < 0.1.1 > Fix: `gem update gollum` will update the dependencies. > Link to vulnerability/fix diff: > https://github.com/gollum/grit_adapter/commit/4520d973c81fecfebbeacd2ef2f1849d763951c7 > Link to project issue: https://github.com/gollum/gollum/issues/913 > > Description: The bug exploits the fact that gollum uses the grit gem for > git repository access, which makes command-line calls to `git grep` to > search files. `git grep` has an `-O` or `--open-files-in-pager` option > which can spawn an arbitrary process (to act as pager). In vulnerable > versions of gollum, searching for the string `-O<arbitrary command>` or > `--open-files-in-pager <arbritary command>` in the wiki's search field > will execute an arbitrary shell command. However, this will only work if > the string "master" (or more precisely, the name of the git branch that > gollum is using) is found in one of the wiki's files: "master" is then > interpreted as the search query, `-O<arbitary code>` as a command line > option to `git grep`. > > The fix in the `gollum-grit_adapter` gem v.0.1.1 shell-escapes the > user's query and removes any -O or --open-file-in-pager option from it. > >  https://github.com/gollum/gollum, https://rubygems.org/gems/gollum >  https://github.com/gollum/grit_adapter >  https://github.com/gollum/gollum-lib >
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