The `git` subcommand `cvsserver` is a Perl script which makes excessive use of the backtick operator to invoke `git`. User input is used within some of those invocations. This potentially allows a local attacker to execute arbitrary code. It should be noted, that `git-cvsserver` will be invoked by `git-shell` by default without further configuration. References: http://seclists.org/oss-sec/2017/q3/534 https://public-inbox.org/git/xmqqy3p29ekj.fsf@gitster.mtv.corp.google.com/
Created git tracking bugs for this issue: Affects: openshift-1 [bug 1496345]
For systems to be vulnerable to the attack documented in http://seclists.org/oss-sec/2017/q3/att-534/git_cvsserver.txt the git-cvs package must be installed. Most modern git servers will not need git-cvs and could remove it to mitigate the vulnerability.
This issue has now been assigned CVE-2017-14867, as noted in http://seclists.org/oss-sec/2017/q3/568.
Created attachment 1334729 [details] git 2.10.4 to 2.10.5 diff Diff of 2.10.4 to 2.10.5. Linking individual commits is a bit messy in this case, so this seems to be the next best option.
Mitigation: In case you do not rely on the commands offered by the "-cvs" subpackage (for example "git cvsserver" or "git cvsimport") on RHEL or RHSCL, you can uninstall the git "-cvs" subpackage.
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2017-14867