Re: Git ransom campaign incident report - May 2019
- Date: Fri, 17 May 2019 18:20:31 -0400
- From: Jeff King <peff@xxxxxxxx>
- Subject: Re: Git ransom campaign incident report - May 2019
On Fri, May 17, 2019 at 09:39:55PM +0200, Johannes Schindelin wrote:
> > Of course I suspect there are many cases where people _do_ need to store
> > the password in plaintext, because an automated system needs to fetch
> > with it. They can use the plaintext git-credential-store, but it's
> > slightly more hassle. And it doesn't really _solve_ the problem (though
> > perhaps it would be harder to accidentally expose it with your web
> > server!).
> One thing that we actually *could* do here is to anonymize the URLs stored
> under remote.origin.url when cloning. In no other circumstance that I can
> think of do we take an URL from some command-line parameter that is not
> *explicitly* intended for storing in the config.
Good point. That's a plausible way that these end up in config even when
they're not needed and it wasn't intended by the user.
> Combined with that warning "You cloned via a URL that contains
> credentials; for security reasons, the credentials were scrubbed before
> storing this in your Git config. Please consider using a credential
> manager instead of storing secrets in your Git config." this should
> provide a reasonable compromise.
Yeah, we'd definitely want to warn the user. Some people might find it
irritating because a follow-up fetch would require an interactive
password. We might need to make sure the escape hatch is pretty turnkey.
The simplest thing is just a "--save-password" option to override this,
but it would be nice if there's an out-of-the-box solution with a
We can use credential-store as a general solution. That's still
sticking the password in the filesystem in plaintext, but the file is
0700 by default, and it's not in the repo directory).
git clone https://user@pass:example.com/repo.git
into a safer use of credential-store is a little tricky, because seeding
the store is generally only done interactively. What if we did this:
1. Do not ever write the password part of a URL into config.
2. When we extract the user/pass out of a URL, put them into the
credential struct, so that when we successfully authenticate, we
trigger storage. This _might_ actually happen already, but we
should definitely confirm it.
3. If the user has no credential helper defined, then do one of:
a. Warn them that the credential was not recorded, but that they
can use "git clone -c credential.helper=store" as a fallback
(but probably worded in a way to recommend using something
stronger if possible).
This is slightly annoying because following the advice requires
re-cloning. Fixing it up from there is more like:
git config credential.helper store
[interactively input password]
b. Just use credential-store. Optionally notify them of what
happened (and that they might want to choose a better helper).
I hate the magical-ness of 3b, because credential-store really _isn't_
the best choice. It's just better than the current behavior. At the same
time, by doing it automatically, the existing flow they were using just
works, and is moderately better.
> Judging from looking at my own automated jobs, it does not appear that you
> would *ever* need to store such credentials in the Git config, anyway. If
> you need to, say, push to a repository, you can always store the full URL
> (or the credentials) in a secret variable.
Yes, that's definitely the way you _should_ do it. I think the problem
is that handling secret storage is tricky and system-specific, and the
people who are affected here are ones who just didn't think about it. If
we can make even a moderate improvement without the user having to do
anything differently, it's worth considering.