A new Linux vulnerability known as '
Looney Tunables' enables local attackers to gain root privileges by exploiting a buffer overflow weakness in the GNU C Library's ld.so dynamic loader.
The GNU C Library (glibc) is the GNU system's C library and is in most Linux kernel-based systems. It provides essential functionality, including system calls like open, malloc, printf, exit, and others, necessary for typical program execution.
The dynamic loader within glibc is of utmost importance, as it is responsible for program preparation and execution on Linux systems that use glibc.
Discovered by the
Qualys Threat Research Unit, the flaw (CVE-2023-4911) was introduced
in April 2021, with the release of glibc 2.34, via a commit described as fixing SXID_ERASE behavior in setuid programs.
"Our successful exploitation, leading to full root privileges on major distributions like Fedora, Ubuntu, and Debian, highlights this vulnerability’s severity and widespread nature,"
said Saeed Abbasi, Product Manager at Qualys' Threat Research Unit.
"Although we are withholding our exploit code for now, the ease with which the buffer overflow can be transformed into a data-only attack implies that other research teams could soon produce and release exploits.
"This could put countless systems at risk, especially given the extensive use of glibc across Linux distributions."
