Description

Unprivileged attackers can gain root access to multiple major Linux distributions in default configurations due to a local privilege escalation (LPE) vulnerability in the GNU C Library (glibc). This security hole, tracked as CVE-2023-6246, occurs when glibc's __vsyslog_internal() function is used to write to the system message logger, which is used by syslog and vsyslog. The bug, introduced in glibc 2.37 in August 2022 and later backported to glibc 2.36, results in a heap-based buffer overflow vulnerability. This flaw poses a significant threat as it enables local privilege escalation, allowing an unprivileged user to gain full root access through crafted inputs to applications using these logging functions. While the vulnerability requires specific conditions to be exploited, such as an unusually long argv[0] or openlog() ident argument, its impact is substantial due to the widespread use of the affected library. According to Qualys security researchers, Debian 12 and 13 as well as Ubuntu 23.04 and 23.10, as well as Fedora 37 to 39 are all vulnerable to CVE-2023-6246 exploits, which may allow unprivileged users to escalate privileges to full root access. Additionally, the researchers found three other vulnerabilities, including two harder-to-exploit issues in __vsyslog_internal() (CVE-2023-6779 and CVE-2023-6780) and a memory corruption issue in glibc's qsort(). These vulnerabilities underscore the critical need for strict security measures in software development, particularly for core libraries widely used across many systems and applications. Over the past few years, Qualys researchers have identified various Linux security vulnerabilities that can lead to complete control over unpatched Linux systems, emphasizing the ongoing importance of addressing and patching such vulnerabilities in a timely manner.