Can someone explain why this is leaky and how it can be exploited by malicious actors?
There is no guarantee that an exposed .gitignore (or other exposed files, like .htaccess, robots.txt, etc) will be exploitable, but they aid in the discovery process and may help adversaries uncover exploitable vulnerabilities they might have otherwise missed.
At the extreme, I've seen paths of backups of the production database listed in a publicly readable .gitignore, and that database backup was publicly accessible, too.
Most of the time, nothing sensitive is revealed, but defense in depth suggests it's better to not upload files like these to your web server unless they're being used by the webserver (like .htaccess) or crawlers (like robots.txt), and if you do, they ought to not be publicly readable (unless intended, like robots.txt), but even then, you'd want to make sure nothing sensitive is in any file like that which is publicly readable. Even if there's nothing sensitive in them now, there's no guarantee that nothing sensitive will ever be added.
I had to work with a security team in a FAANG for several years. They were so high and mighty with their low sev vulnerabilities, but they never improved security, and refused to acknowledge recommendations from the engineers working on systems that needed to be rearchitected due to a fundamental problems with networking, security boundaries, root of trust, etc. Unsurprisingly, their "automated scanner" failed to catch something a SRE would have spotted in 5 minutes, and the place got owned in a very public and humiliating way.
When I see things like this it brings back memories of that security culture. Frankly I think Infosec is deeply broken and gawking over a wild .gitignore is a perfect example of that.
There's no guarantee any of your testers will find every issue, and there's no guarantee that a seemingly innocuous finding can't have a greater impact than might readily be apparent.
That said, there are a ton of charlatans in security exactly like you describe - folks who can't read code (let alone write it) who just know how to click "scan" on their GUI tools and export the report to a PDF. A lot orgs have a QA-level team running those automated scans, which get passed on to a penetration testing team, who have more experience, but a limited time window for testing, and then finally on to red teams, who, along with some appsec / product security folks who are embedded directly on product teams, tend to have the most expertise, and the most time to really dive deeply into a service or application.
Also, keep in mind that those gawking over this probably aren't security folks, and the competent security folks here may not be gawking at the file itself (or others) - just taking part in the discussion.
Absolutely this. Security often has a different perspective as to how systems may be exploited together to create a systemic issue where none exists independently. Of course, this is often also where security fails in communicating exactly why these low severity issues must be corrected and facilitating an engineering discussion as to how the attack chain can be effectively disrupted and detective controls implemented elsewhere in the chain such that attempts to exploit are detected.
In short, the failure isn't in finding the threat but in dictating solutions without getting everyone involved in engineering the interaction in the room, so to speak.
I would be ideal to have security engineering as an embedded function representing red and blue team findings as systems requirements and acting as a single point contact in regards to security issues such that mutual trust and respect may be developed.
I'm not disappointed this happens at tesla.com; I expect as much. But to many people, this is a top-notch brand. You don't expect this on google.com or nsa.gov or fbi.gov either, do you?
It is a bit embarrassing because most web servers (and deployment setups) shouldn't be publishing/serving dot files anyway (files with names beginning with dot). But it's not necessarily a problem as long as they have some protection to avoid the _really_ sensitive stuff leaking, it's just kind of funny.
In practice, it means that if the gitignore file is leaked, that there is a substantial risk that they accidentally leak the .git folder someday.
The .git folder indirectly contains downloadable copies of the source-code of the website, which could very likely lead to credentials leak or compromised services.
Your life can depend on Tesla.com services.
Even if you are the pedestrian side.
If you can grab credentials from there you can do quite some things already.
See https://www.teslaapi.io/authentication/oauth (and this is in the case you don't trick an employee).
But I agree, that normally at some point they would catch it.
FTFY. Little of Tesla's software is whatever they're using on the website. That'd be like judging Apple OS software by their website source.
On the same domain there is also the Tesla SSO.
It would be bad if this gets compromised as there would be direct impact in the physical world, not just a static landing somewhere.
So, not very surprising and probably doesn't really tip anyone towards anything particularly special.
Otherwise, it's not much of a leak.
ie, if the file said to ignore "/site/adminpasswords.txt" then you could go to /site/adminpasswords.txt and reveal admin passwords. this is obviously a simple eli5 explanation but i hope it helps
however, i doubt the tesla.com website is where they keep any important code that relates to actual tesla software like we would see used in cars. that would be like the army having their real code for their software/systems at goarmy.com lol