CVE-2021-3115 in Google
Summary
by MITRE • 01/26/2021
Go before 1.14.14 and 1.15.x before 1.15.7 on Windows is vulnerable to Command Injection and remote code execution when using the "go get" command to fetch modules that make use of cgo (for example, cgo can execute a gcc program from an untrusted download).
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/20/2021
The vulnerability identified as CVE-2021-3115 represents a critical command injection flaw in the go programming language toolchain affecting versions prior to 1.14.14 and 1.15.7 on windows platforms. This vulnerability specifically targets the go get command which is commonly used to fetch and install go modules from remote sources. The flaw arises from the improper handling of cgo directives within downloaded modules, creating an environment where malicious code can be executed with the privileges of the user running the go get command.
The technical implementation of this vulnerability stems from how the go toolchain processes cgo directives during module acquisition. When a module contains cgo directives that reference external build tools or compilers, the go get command may execute these directives without proper sanitization of input parameters. This creates a command injection vector where untrusted code can manipulate the build process to execute arbitrary commands on the target system. The vulnerability is particularly dangerous because it leverages the legitimate functionality of cgo to execute gcc programs from untrusted downloads, making it difficult to distinguish between benign and malicious code at runtime.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise when exploited. An attacker could potentially upload a malicious go module containing cgo directives that execute harmful commands such as downloading additional malware, establishing reverse shells, or modifying system configurations. The vulnerability affects the entire go ecosystem on windows systems, making it a widespread concern for organizations using go for development or deployment purposes. The attack vector requires minimal privileges and can be exploited through standard go get operations, making it particularly dangerous in automated build environments or continuous integration systems where go get commands are frequently executed.
Organizations should immediately upgrade to go versions 1.14.14 or 1.15.7 and later to mitigate this vulnerability. Additional mitigations include implementing network segmentation to restrict access to trusted module repositories, enabling strict module verification through go mod verify, and monitoring build systems for suspicious go get operations. The vulnerability aligns with CWE-78 which describes improper neutralization of special elements used in OS commands, and maps to ATT&CK technique T1059.001 for command and scripting interpreter. Security teams should also consider implementing automated scanning of go modules for potentially malicious cgo usage patterns and establish secure development practices that minimize reliance on external modules with cgo directives. Organizations using go in production environments should conduct immediate vulnerability assessments to identify systems running affected versions and implement comprehensive patch management procedures to ensure all go toolchains remain current with security updates.