CVE-2017-15041 in Google
Summary
by MITRE
Go before 1.8.4 and 1.9.x before 1.9.1 allows "go get" remote command execution. Using custom domains, it is possible to arrange things so that example.com/pkg1 points to a Subversion repository but example.com/pkg1/pkg2 points to a Git repository. If the Subversion repository includes a Git checkout in its pkg2 directory and some other work is done to ensure the proper ordering of operations, "go get" can be tricked into reusing this Git checkout for the fetch of code from pkg2. If the Subversion repository's Git checkout has malicious commands in .git/hooks/, they will execute on the system running "go get."
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability described in CVE-2017-15041 represents a critical remote command execution flaw in the go get command of the golang ecosystem. This security issue affects Go versions prior to 1.8.4 and 1.9.1, creating a dangerous condition where attackers can manipulate the package retrieval process to execute arbitrary commands on systems running vulnerable versions. The vulnerability exploits the way Go handles repository resolution when multiple version control systems are involved, specifically targeting the interaction between Subversion and Git repositories within the same domain structure.
The technical flaw stems from Go's package resolution mechanism that does not properly isolate repository contexts when dealing with mixed version control systems. When a domain contains both Subversion and Git repositories, Go's package fetching logic can be manipulated through carefully crafted domain structures where subdirectories point to different repository types. This creates an opportunity for attackers to place malicious Git hooks within a Subversion repository's Git checkout directory, which then executes when Go attempts to fetch packages from the subdirectory. The vulnerability specifically leverages the fact that Go's package management system does not adequately validate or isolate repository contexts, allowing for cross-repository contamination.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary commands on systems with vulnerable Go installations simply by manipulating package URLs or domain configurations. This creates a vector for privilege escalation and system compromise, as the malicious commands execute with the privileges of the user running the go get command. The attack requires minimal user interaction beyond running the go get command, making it particularly dangerous in automated build environments or when developers routinely fetch packages from untrusted sources. The vulnerability essentially allows attackers to inject malicious code into the build process without requiring direct access to the target system, making it a significant concern for development environments and continuous integration pipelines.
Mitigation strategies for CVE-2017-15041 include immediate upgrading to Go versions 1.8.4 or 1.9.1 and later, which contain fixes for the repository context isolation issue. Organizations should also implement strict package source verification practices, avoiding the use of untrusted package sources and implementing network segmentation to limit access to external package repositories. Additionally, security teams should monitor and audit development environments for any malicious package dependencies that might have been introduced through compromised package repositories. The vulnerability aligns with CWE-434, which addresses the insecure upload of code, and represents a specific case where the ATT&CK technique T1059.001 for command and script injection is enabled through package management systems rather than traditional attack vectors.
This vulnerability highlights the importance of proper repository context management in package managers and demonstrates how seemingly innocuous package resolution logic can create dangerous security holes. The fix implemented in Go 1.8.4 and 1.9.1 specifically addresses the repository reuse issue by ensuring proper isolation between different version control systems within the same domain structure. Organizations should also consider implementing automated security scanning of package dependencies and establishing secure development practices that minimize exposure to such vulnerabilities in their build environments.