GHSA-7w47-3wg8-547c CVE-2024-35186 RUSTSEC-2024-0348 RUSTSEC-2024-0349 RUSTSEC-2024-0350
gix traversal outside working tree enables arbitrary code execution
High
crates.io
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.82%
- Chance of exploitation in the next 30 days. Higher than 57.10% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
- CWE-23 Relative Path Traversal
- Fix
- Available
- 7 packages have a fixed version
Description
Summary
During checkout, gitoxide does not verify that paths point to locations in the working tree. A specially crafted repository can, when cloned, place new files anywhere writable by the application.
Details
Although gix-worktree-state checks for collisions with existing files, it does not itself check if a path is really in the working tree when performing a checkout, nor do the path checks in gix-fs and gix-worktree prevent this. Cloning an untrusted repository containing specially crafted tree or blob names will create new files outside the repository, or inside the repository or a submodule's .git directory. The simplest cases are:
- A tree named
..to traverse upward. This facilitates arbitrary code execution because files can be placed in one or more locations where they are likely to be executed soon. - A tree named
.gitto enter a.gitdirectory. This facilitates arbitrary code execution because hooks can be installed.
A number of alternatives that achieve the same effect are also possible, some of which correspond to specific vulnerabilities that have affected Git in the past:
- A tree or blob whose name contains one or more
/, to traverse upward or downward. For example, even without containing any tree named..or.git, a repository can represent a file named../outsideor.git/hooks/pre-commit. This is distinct from the more intuitive case a repository containing trees that represent those paths. - In Windows, a tree or blob whose name contains one or more
\, to traverse upward or downward. (Unlike/, these are valid on other systems.) See GHSA-xjx4-8694-q2fq. - On a case-insensitive filesystem (such as NTFS, APFS, or HFS+), a tree named as a case variant of
.git. - On HFS+, a tree named like
.gitor a case variant, with characters added that HFS+ ignores in collation. See https://github.com/git/git/commit/6162a1d323d24fd8cbbb1a6145a91fb849b2568f. - On NTFS, a tree equivalent to
.git(or a case variant) by the use of NTFS stream notation, such as.git::$INDEX_ALLOCATION. See GHSA-5wph-8frv-58vj. - On an NTFS volume with 8.3 aliasing enabled, a tree named as
git~1(or a case variant). See GHSA-589j-mmg9-733v.
When a checkout creates some files outside the repository directory but fails to complete, the repository directory is usually removed, but the outside files remain.
PoC
For simplicity, these examples stage a stand-in file with a valid name, modify the index, and commit. The instructions assume sed supports -i, which is the case on most systems. If using Windows, a Git Bash shell should be used.
Example: Downward traversal to install hooks
- Create a new repository with
git init dangerous-repo-installs-hookandcdinto the directory. - Create the stand-in called
.git@hooks@pre-commit, with the contents:#!/bin/sh printf 'Vulnerable!\n' date >vulnerable - Stage the stand-in:
git add --chmod=+x .git@hooks@pre-commit - Edit the index:
env LC_ALL=C sed -i.orig 's|\.git@hooks@pre-commit|.git/hooks/pre-commit|' .git/index - Commit:
git commit -m 'Initial commit' - Optionally, push to a private remote.
Then, on another or the same machine:
- Clone the repository with a
gix clone …command. - Enter the newly created directory.
- Optionally run
ls -l .git/hooksto observe that thepre-commithook is already present. - Make a new file and commit it with
git. This causes the payload surreptitiously installed as apre-commithook to run, printing the messageVulnerable!and creating a file in the current directory containing the current date and time.
Note that the effect is not limited to modifying the current directory. The payload could be written to perform any action that the user who runs git commit is capable of.
Example: Upward traversal to create a file above the working tree
- Create a new repository with
git init dangerous-repo-reaches-up, andcdinto the directory. - Create the stand-in:
echo 'A file outside the working tree, somehow.' >..@outside - Stage the stand-in:
git add ..@outside - Edit the index:
env LC_ALL=C sed -i.orig 's|\.\.@outside|../outside|' .git/index - Commit:
git commit -m 'Initial commit' - Optionally, push to a private remote.
Then, as above, on the same or another machine, clone the repository with a gix clone … command. Observe that a file named outside is present alongside (not inside) the cloned directory.
Impact
Any use of gix or another application that makes use of gix-worktree-state, or otherwise relies on gix-fs and gix-worktree for validation, is affected, if used to clone untrusted repositories. The above description focuses on code execution, as that leads to a complete loss of confidentiality, integrity, and availability, but creating files outside a working tree without attempting to execute code can directly impact integrity as well.
In use cases where no untrusted repository is ever cloned, this vulnerability has no impact. Furthermore, the impact of this vulnerability may be lower when gix is used to clone a repository for CI/CD purposes, even if untrusted, since in such uses the environment is usually isolated and arbitrary code is usually run deliberately from the repository with necessary safeguards in place.
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| gitoxide | < 0.36.0 |
0.36.0 |
| gitoxide-core | < 0.38.0 |
0.38.0 |
| gix | < 0.63.0 |
0.63.0 |
| gix-fs | < 0.11.0 |
0.11.0 |
| gix-fs | >= 0.0.0-0, < 0.11.0 |
0.11.0 |
| gix-index | < 0.33.0 |
0.33.0 |
| gix-index | >= 0.0.0-0, < 0.33.0 |
0.33.0 |
| gix-worktree | < 0.34.0 |
0.34.0 |
| gix-worktree | >= 0.0.0-0, < 0.34.0 |
0.34.0 |
| gix-worktree-state | < 0.11.0 |
0.11.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
gitoxide crates.io → 0.36.0
- cargo
cargo update -p gitoxide --precise 0.36.0
gitoxide-core crates.io → 0.38.0
- cargo
cargo update -p gitoxide-core --precise 0.38.0
gix crates.io → 0.63.0
- cargo
cargo update -p gix --precise 0.63.0
gix-fs crates.io → 0.11.0
- cargo
cargo update -p gix-fs --precise 0.11.0
gix-index crates.io → 0.33.0
- cargo
cargo update -p gix-index --precise 0.33.0
gix-worktree crates.io → 0.34.0
- cargo
cargo update -p gix-worktree --precise 0.34.0
gix-worktree-state crates.io → 0.11.0
- cargo
cargo update -p gix-worktree-state --precise 0.11.0
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- Active
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- High
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How to prevent it
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would b
- Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked. Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes: realpath() in C getCanonicalPath() in Java GetFullPath() in ASP.NET realpath() or abs_path() in Perl realpath() in PHP
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
- Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
- Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
- Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Architecture and Design, Operation: Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately. This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not. In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.
- Operation, Implementation: When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
CWE-23: Relative Path Traversal
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.
How to prevent it
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would b
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked. Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes: realpath() in C getCanonicalPath() in Java GetFullPath() in ASP.NET realpath() or abs_path() in Perl realpath() in PHP
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-q54r-jf2p-rfr2 gitoxide gix: untrusted .git/config disables filesystem .git-protection path checks via unfiltered protect_options() | High | Also affects gix |
| GHSA-fr8x-3vfx-f45h gix and gitoxide: unvalidated submodule name traverses out of .git/modules and redirects state() / open() to another repository | High | Also affects gitoxide |
| GHSA-pg4w-g64p-qwhj gix and gitoxide's symlinked .gitmodules are followed and parsed from outside of the repository | High | Also affects gitoxide |
| GHSA-f26g-jm89-4g65 gitoxide: CommandForbiddenInModulesConfiguration Bypass in gix_submodule::File::update() Enables Arbitrary Command Execution via .gitmodules | High | Also affects gix |
| GHSA-p3hw-mv63-rf9w gix's submodule name validation bypass + trust inheritance flaw enables path traversal and credential disclosure | High | Also affects gix |
| GHSA-2frx-2596-x5r6 gitoxide does not detect SHA-1 collision attacks | Medium | Also affects gitoxide |
| GHSA-88g2-r9rw-g55h gitoxide-core does not neutralize special characters for terminals | Low | Also affects gitoxide |
| GHSA-49jc-r788-3fc9 gix refs and paths with reserved Windows device names access the devices | Medium | Also affects gitoxide |
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