Introduction to Sudo Attacks and Privilege Escalation on Linux
In the world of Linux-based operating systems, the sudo command plays a critical role in user privilege management. It allows permitted users to execute commands as the superuser (root) or another user, as specified by the security policy. However, various vulnerabilities have been discovered in sudo that can lead to privilege escalation, allowing unauthorized users to gain elevated access to system resources.
This discussion centers around several notable vulnerabilities, including CVE-2019-14287 and CVE-2019-18634, which have garnered attention for their potential to exploit the sudo command for malicious purposes. These vulnerabilities demonstrate the importance of understanding how sudo can be misconfigured or manipulated, leading to security breaches.
Topics to Discuss
CVE-2019-14287: CVE-2019-14287 is a vulnerability in
sudothat allows a user with restricted privileges to execute arbitrary commands as root, even if they are explicitly denied in thesudoersfile. This occurs due to improper validation of the user ID (UID) when running commands.CVE-2019-18634: CVE-2019-18634 is a buffer overflow vulnerability in
sudothat can allow local privilege escalation. It specifically affectssudoconfigurations where pwfeedback is enabled, which can result in memory corruption and potentially lead to unauthorized code execution or system crashes.Shell Escaping: This topic focuses on the concept of shell escaping in command execution, particularly when arguments passed to the shell are not properly sanitized. Attackers can craft malicious input to manipulate shell behavior, leading to unintentional command executions with elevated privileges.
LD_PRELOAD: This is an environment variable that can be exploited to execute malicious shared libraries before any other libraries when running a program. By using
LD_PRELOAD, attackers can intercept and modify calls to system functions within programs invoked withsudo, paving the way for privilege escalation.