IT Forensics · Linux

Forensic analysis of PAM configuration – correctly classifying authentication modules

Under Linux, Pluggable Authentication Modules (PAM) centrally control how authentication processes for a wide variety of services are carried out, ranging from local log-in to SSH and sudo access.

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As PAM intervenes deeply in the authentication process, a tampered PAM configuration can be exploited to intercept login credentials or create additional, covert access routes.

Why LanCologne?

Since its foundation, LanCologne has specialised in professional IT forensics. Our staff have decades of experience in the field of information technology and assist companies, solicitors, private individuals and, on a regular basis, the courts in the technical investigation of complex digital matters.

The examination is, as a matter of principle, carried out exclusively on a forensic copy, a forensic image or a data source captured in a technically equivalent manner that preserves the integrity of the evidence. The original evidence remains unchanged and is stored in a manner that preserves its integrity.

Our services

We systematically analyse the existing PAM configuration, check integrated modules for anomalies and investigate any indications of subsequent tampering aimed at compromising access credentials.

Typical areas of application

Investigation of manipulated authentication mechanisms
Detection of credential theft via PAM modules
Analysis of additional, covertly established access routes
Assessment of a system’s authentication security
Incident Response on Linux Systems
Judicial and non-judicial expert reports

This is how a PAM analysis works

Once the system has been backed up, the complete PAM configuration for all relevant services is recorded. Integrated modules are checked for their origin and integrity, with particular attention paid to modules that have been added or modified subsequently. Any anomalies are cross-checked against authentication logs.

Why is PAM analysis relevant in a forensic context?

A compromised PAM configuration may enable an attacker to gain persistent and undetectable access, for example through an additional, covertly integrated authentication module.

As PAM affects virtually all of a system’s authentication processes, a breach at this stage can have particularly far-reaching consequences and is therefore investigated with the utmost care should any suspicion arise.

Frequently Asked Questions

What is PAM?+
A modular framework that centrally manages authentication for various services on Linux and makes it configurable.
Can PAM be misused to intercept passwords?+
Yes, a tampered module can log any login details entered or pass them on to third parties.
How can manipulation be detected?+
By checking the origin and integrity of the modules and comparing them with known standard configurations for the respective distribution.

LanCologne – Linux Forensics Cologne

Do you require a professional forensic investigation into „forensic analysis of PAM configuration"? LanCologne can assist you with the court-admissible preservation of digital evidence and the transparent analysis of relevant Linux artefacts.

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