CVE-2022-39260

Git is an open source, scalable, distributed revision control system. git shell is a restricted login shell that can be used to implement Gits push/pull functionality via SSH. In versions prior to 2.30.6, 2.31.5, 2.32.4, 2.33.5, 2.34.5, 2.35.5, 2.36.3, and 2.37.4, the function that splits the command arguments into an array improperly uses an int to represent the number of entries in the array, allowing a malicious actor to intentionally overflow the return value, leading to arbitrary heap writes. Because the resulting array is then passed to execv(), it is possible to leverage this attack to gain remote code execution on a victim machine. Note that a victim must first allow access to git shell as a login shell in order to be vulnerable to this attack. This problem is patched in versions 2.30.6, 2.31.5, 2.32.4, 2.33.5, 2.34.5, 2.35.5, 2.36.3, and 2.37.4 and users are advised to upgrade to the latest version. Disabling git shell access via remote logins is a viable short-term workaround.

Weakness

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Software

Name	Vendor	Start Version	End Version
Git	Git-scm	*	2.30.6 (excluding)
Git	Git-scm	2.31.0 (including)	2.31.5 (excluding)
Git	Git-scm	2.32.0 (including)	2.32.4 (excluding)
Git	Git-scm	2.33.0 (including)	2.33.5 (excluding)
Git	Git-scm	2.34.0 (including)	2.34.5 (excluding)
Git	Git-scm	2.35.0 (including)	2.35.5 (excluding)
Git	Git-scm	2.36.0 (including)	2.36.3 (excluding)
Git	Git-scm	2.37.0 (including)	2.37.4 (excluding)
Git	Git-scm	2.38.0 (including)	2.38.0 (including)
Red Hat Enterprise Linux 8	RedHat	git-0:2.39.1-1.el8	*
Red Hat Enterprise Linux 8.6 Extended Update Support	RedHat	git-0:2.31.8-1.el8_6	*
Red Hat Enterprise Linux 9	RedHat	git-0:2.39.1-1.el9	*
Git	Ubuntu	bionic	*
Git	Ubuntu	devel	*
Git	Ubuntu	esm-infra/xenial	*
Git	Ubuntu	focal	*
Git	Ubuntu	jammy	*
Git	Ubuntu	kinetic	*
Git	Ubuntu	lunar	*
Git	Ubuntu	trusty	*
Git	Ubuntu	xenial	*

Potential Mitigations

Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

https://cwe.mitre.org/data/definitions/92.html

NVD	https://nvd.nist.gov/vuln/detail/CVE-2022-39260
CWE	https://cwe.mitre.org/data/definitions/122.html

Heap-based Buffer Overflow

Weakness

Affected Software

Potential Mitigations

References

CVE-2022-39260

Heap-based Buffer Overflow

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References