Security

Investigating Group Permission Issues When Linux users report issues accessing files and directories with their group permissions, the first troubleshooting step is to verify proper group membership. Use the ‘groups’ and ‘id’ commands to validate the user is in the expected groups. Check the file and directory permissions with ‘ls -l’ to ensure the group…

Assessing Your System’s Vulnerabilities Conducting a thorough assessment of potential vulnerabilities is a critical first step towards securing a Linux system. Unpatched flaws in the operating system, misconfigured services, and unnecessary packages can all introduce weaknesses that could be exploited by an attacker. Scanning for Known Vulnerabilities with Tools like Lynis and OpenSCAP Vulnerability scanners…

Mitigating the Risks of Unsecure Shell Scripts Shell scripts provide a convenient way to automate tasks on Linux and Unix-based systems. However, unsecure shell scripts can expose systems to significant risks. Flaws in shell scripts may enable arbitrary code execution, allowing attackers to execute malicious commands and take control of systems. Arbitrary code execution through…

The Risks of Unchecked User Input in Shell Scripts Shell scripts can execute system commands via user input without proper validation. This allows attackers to inject additional malicious commands giving them unauthorized system access. Potential damages include sensitive data theft, malware installation, and container escape. Shell scripts use interpretation to execute commands from user input….

The Security Risks of Setuid Shell Scripts Setting the setuid permission on shell scripts allows them to run with the privileges of the file owner, rather than the user executing them. However, this also introduces significant security risks if not managed properly. The elevated privileges can be leveraged by an attacker to escalate privileges, execute…

Understanding Environment Variable Vulnerabilities Environment variables provide a way for processes to configure their runtime environments. However, malicious actors can take advantage of how Linux handles environment variables to escalate privileges, bypass security controls, or achieve remote code execution. Developers must understand common attack techniques in order to effectively defend against them. How Malicious Actors…

The Problem with Setuid Security The setuid security mechanism in Linux and UNIX operating systems allows programs to run with the permissions of the file owner rather than the permissions of the user executing the program. This enables normal users to perform privileged operations. However, the setuid design contains inherent vulnerabilities that can allow attackers…

What are Capabilities and Why Do We Need Them? The traditional Unix security model grants full privileged access to the root user. This “all or nothing” approach means that any program running as root or setuid root can access all files and perform any system modification. However, many programs do not need full root access…

Hardening Unix Systems Against Attacks Unix systems connected to networks are under constant threat of cyber attacks. A compromised server can lead to data breaches, ransomware attacks, cryptojacking, and more. That’s why hardening and securing Unix systems is critical for organizations. Here are some best practices to secure your Unix servers, workstations, and devices: Enabling…

Defining the Core Problem Unix systems have inherent tensions between maintaining security and providing usability. Administrators aim to lock down systems and strictly control access, while users need productivity and flexibility. This leads to common pain points: Administrators struggle with granting permissions, leading to either overly restricted or excessively open access Users face authentication barriers,…