CVE-2023-29405 in cmd-go
Summary
by MITRE • 06/09/2023
The go command may execute arbitrary code at build time when using cgo. This may occur when running "go get" on a malicious module, or when running any other command which builds untrusted code. This is can by triggered by linker flags, specified via a "#cgo LDFLAGS" directive. Flags containing embedded spaces are mishandled, allowing disallowed flags to be smuggled through the LDFLAGS sanitization by including them in the argument of another flag. This only affects usage of the gccgo compiler.
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Analysis
by VulDB Data Team • 01/07/2025
The vulnerability identified as CVE-2023-29405 represents a critical security flaw in the go command's handling of cgo build processes specifically when utilizing the gccgo compiler. This vulnerability enables arbitrary code execution during build time, creating a significant attack surface that can be exploited through various means including malicious module retrieval or any command that builds untrusted code. The flaw stems from improper sanitization of linker flags within the cgo directive structure, specifically the "#cgo LDFLAGS" directive that governs how linker flags are processed during compilation. The security implications extend beyond simple code execution to potentially allow attackers to escalate privileges or compromise entire build environments when developers unknowingly incorporate malicious dependencies into their projects.
The technical mechanism behind this vulnerability involves the mishandling of linker flags that contain embedded spaces, which creates a path for malicious flag smuggling through the LDFLAGS sanitization process. When the go command processes cgo directives, it fails to properly validate or parse linker flags that contain spaces, allowing attackers to craft malicious flag sequences that bypass security checks. This parsing error enables disallowed flags to be embedded within the argument of another flag, effectively creating a bypass mechanism that circumvents the intended sanitization controls. The vulnerability specifically affects the gccgo compiler implementation, distinguishing it from other go toolchain components that may handle similar scenarios more securely. This particular weakness demonstrates a classic command injection vulnerability pattern where user-supplied input is not properly escaped or validated before being processed by the underlying build system.
The operational impact of this vulnerability extends far beyond individual development environments as it can compromise entire software supply chains when developers use "go get" to retrieve dependencies from untrusted sources. Any command that triggers the building of untrusted code, including but not limited to go build, go install, or go test operations, can potentially be exploited to execute arbitrary code on the build system. The risk is particularly elevated in continuous integration environments where automated build processes may unknowingly pull and compile malicious modules from public repositories. Attackers can leverage this vulnerability to inject malicious code into legitimate projects, potentially creating backdoors or other persistent threats that remain undetected until deployed to production environments. This vulnerability also impacts organizations that rely on go-based tools for infrastructure automation or cloud-native application development, as these systems often incorporate third-party dependencies without thorough security verification.
Mitigation strategies for CVE-2023-29405 should focus on immediate remediation through go toolchain updates that address the flag parsing vulnerability in gccgo compiler implementations. Organizations should implement strict dependency management practices including the use of go.mod checksum verification, private module repositories, and comprehensive security scanning of all dependencies before integration into development workflows. The implementation of build environment isolation and sandboxing techniques can provide additional protection layers against potential exploitation attempts. Security teams should also consider implementing network segmentation to prevent automated build systems from accessing untrusted module repositories without proper security controls. According to CWE standards, this vulnerability maps to CWE-78 and CWE-74, which address command injection and improper neutralization of special elements used in OS commands. From an ATT&CK framework perspective, this vulnerability aligns with T1059.001 for command and scripting interpreter and T1133 for external remote services, as it enables attackers to execute arbitrary code through legitimate build processes and potentially establish persistent access through compromised build systems.