Privilege Escalation with Lnav: Risks and Mitigations

Lnav, the popular log file navigator, is fast and convenient. But when misconfigured or paired with certain environments, it can become a path for privilege escalation. This isn’t a theoretical weakness. It’s a real chain attackers can use to pivot from limited shell sessions into root access.

Privilege escalation with Lnav often targets two areas: unsafe execution of embedded scripts and improper file permissions. Lnav supports reading logs, running SQL queries on them, and executing external commands for custom views. If the binary is setuid, or if it runs as a more privileged user in automated workflows, these features can be abused.

One common vector involves crafting a configuration or format file that Lnav loads automatically. If Lnav has permission to invoke system commands through this file, an attacker can run arbitrary code. Combined with elevated execution rights, this is enough to break containment.

Another frequent vector is symbolic link abuse. If Lnav processes log files in directories with weak permissions, attackers can replace them with symlinks to sensitive system files. Certain Lnav functions can then open or overwrite these targets with higher privileges than intended.

Mitigating the risk requires tightening file permissions, disabling dangerous integrations, and never granting Lnav unnecessary elevation. Monitor binary capabilities, check for setuid/setgid bits, and audit any automation scripts that call Lnav. In containerized environments, ensure Lnav runs as a non-root user and cannot escape its assigned volume.

For defenders, these checks are not optional. A single overlooked detail can let a low-privilege user climb to root via a legitimate tool. For attackers, the path is straightforward once the weaknesses align.

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