Critical Git Security Vulnerability Announced

An anonymous reader writes Github has announced a security vulnerability and has encouraged users to update their Git clients as soon as possible. The blog post reads in part: "A critical Git security vulnerability has been announced today, affecting all versions of the official Git client and all related software that interacts with Git repositories, including GitHub for Windows and GitHub for Mac. Because this is a client-side only vulnerability, github.com and GitHub Enterprise are not directly affected. The vulnerability concerns Git and Git-compatible clients that access Git repositories in a case-insensitive or case-normalizing filesystem. An attacker can craft a malicious Git tree that will cause Git to overwrite its own .git/config file when cloning or checking out a repository, leading to arbitrary command execution in the client machine. Git clients running on OS X (HFS+) or any version of Microsoft Windows (NTFS, FAT) are exploitable through this vulnerability. Linux clients are not affected if they run in a case-sensitive filesystem....Updated versions of GitHub for Windows and GitHub for Mac are available for immediate download, and both contain the security fix on the Desktop application itself and on the bundled version of the Git command-line client."

Comments

Unrelated to Github

[Anonymous Coward]

I'm puzzled that Github is stated as the main actor here. They are just
broadcasting the official announcement from the git mailing list. They are not
involved in the initial discovery, subsequent investigations or fixes. How come
this post end up giving them most of the credit? Have people already
forgot that Git and Github are different entities?

Re:I blame Microsoft

[cbhacking]

Actually, Microsoft themselves has an API for accessing NTFS drives in a case-sensitive manner, and I'm not talking about the native NT API or even the FILE_FLAG_POSIX_SEMANTICS Win32 file API flag. All versions of NT from 3.1 (the first) to 6.2 (Win8; it was removed from 8.1) have support for a POSIX operating environment - basically a full Unix-like OS running atop the NT kernel - and for proper Unix-like-ness it is case sensitive.

Mind you, Win32 programs do tend to get confused by it all. For example, CMD's "dir" command will list both "test.txt" and "TEST.TXT" in the same directory, and even correctly note if they have different sizes or datestamps. However, the "type" command (print file contents) on *either* name (or some other-cased version of the name) will instead print the contents of one of the files - doesn't matter what you type, the OS will pick - and it will print it twice (once for each copy of the file with that name).

I've been using the Interix (name of the Unix-like operating environment that runs in the NT POSIX subsystem, as reported by the uname command) build of git for years now. I should probably stop - the repo my package manager used has died, and I haven't bothered to set up a different package manager yet so my packages are outdated - but I am, humorously enough, not vulnerable to this particular attack even with that outdated version.