Uutils Coreutils Printenv Utility Invalid UTF-8 Environment Variable Handling Vulnerability

A vulnerability exists in the printenv utility of uutils coreutils, specifically in version 0.6.0, regarding its handling of environment variables with invalid UTF-8 byte sequences. While POSIX allows arbitrary bytes in environment strings, the uutils coreutils implementation omits these variables without notification. This behavior can prevent malicious environment variables, such as harmful LD_PRELOAD values, from being detected by administrators or security auditing tools, potentially facilitating undetected library injection or other environment-based attacks.

Impact

The vulnerability can lead to the unintentional omission of environment variables with invalid UTF-8, which may be exploited to evade administrative oversight or security audits. This could allow maliciously crafted environment variables to go unnoticed, potentially leading to unauthorized actions or compromises, such as library injection attacks.

Reproduction

To reproduce this vulnerability, set an environment variable with an invalid UTF-8 byte sequence, such as a character that is not representable in UTF-8, like a byte with the value 255. Then, use the printenv command to display the value of the variable. The uutils coreutils version of printenv will not show the variable, while the GNU version will display it correctly.

Remediation

Users can update to uutils coreutils version 0.6.0, which includes a fix for this issue. The updated version can be downloaded from the uutils coreutils GitHub releases page.