Affected: Homebrew: git-annex

# *git-annex* command injection via malicious SSH hostname

*git-annex* was vulnerable to the same class of security hole as git's **CVE-2017-1000117**. In several cases, `git-annex` parses a repository URL, and uses it to generate a `ssh` command, with the hostname to ssh to coming from the URL. If the hostname it parses is something like `-eProxyCommand=evil`, this could result in arbitrary local code execution.

Some details of URL parsing may prevent the exploit working in some cases.

Exploiting this would involve the attacker tricking the victim into adding a remote something like `ssh://-eProxyCommand=evil/blah`.

One possible avenue for an attacker that avoids exposing the URL to the user is to use `initremote` with an SSH remote, so embedding the URL in the *git-annex* branch. Then the victim would enable it with `enableremote`.

This was fixed in version **6.20170818**. Now there's a `SshHost` type that is not allowed to start with a dash, and every invocation of `git-annex` uses a function that takes a `SshHost`.

Mercurial prior to 4.3 did not adequately sanitize hostnames passed to ssh, leading to possible shell-injection attacks.