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Gorbe Technical Blog

website·Indexed 32 days ago

https://gorbe.io

A collection of technical guides and tutorials covering Linux administration, cybersecurity, and self-hosting. Topics include Debian server setup, CEH v10 learning materials, OWASP Top 10, and configurations for tools like Docker, Proxmox, MariaDB, PostgreSQL, and Nginx.

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What's inside Gorbe

  1. Overview of PINENTRY front-end flavors

    PINENTRY is a GUI application for entering PINs or passphrases. Depending on the environment and available toolkits, several flavors are available:

    • pinentry-gtk: GTK+ based
    • pinentry-qt: QT based
    • pinentry-curses: Non-graphical, uses curses (fallback for GUI flavors if DISPLAY is not set)
    • pinentry-tty: Simple terminal, no dependencies
    • Other variants include EFL, FLTK, Gnome 3, and Emacs.

    Security Note: Minimalist variants like pinentry-tty or pinentry-curses run on a fixed virtual console are generally more secure as they reduce the software stack handling the passphrase in memory.

  2. Understand the IoT Architecture Layers

    IoT systems are generally structured into five functional layers:

    1. Perception Layer: Sensors that gather environmental data (e.g., heat sensors).
    2. Transport Layer: Network protocols used to transfer sensor data (e.g., Wi-Fi, Bluetooth).
    3. Processing Layer: Infrastructure for storing, processing, and analyzing data (e.g., cloud computing, big data).
    4. Application Layer: Delivery of specific services to the end user.
    5. Business Layer: Management of the overall system, including privacy and profit models.

  3. Analyze Trojan horse infection and construction

    Trojans mislead users about their true intention and are typically spread via social engineering. They are used to create backdoors, steal information, launch ransomware, or recruit victims into botnets.

    Infection Process:

    1. Creating the trojan
    2. Creating a dropper (designed to deliver the payload and install malware undetected)
    3. Creating a wrapper (binds the malicious file with a popular executable like a game to avoid detection)
    4. Propagating the trojan
    5. Executing the dropper

    Construction Tools:

    • Crypters: Used to encrypt, obfuscate, and manipulate malware to evade detection (e.g., Cryogenic Crypter, Heaven Crypter, Swayz Cryptor).
    • Construction Kits: Tools like Dark Horse, Senna Spy Generator, and Pandora’s Box allow attackers to create trojans that avoid standard scanning.

  4. OWASP Top 10 - 2021 Critical Security Risks Overview

    The OWASP Top 10 - 2021 identifies the most critical web application security risks. The 2021 edition shifts focus toward root causes rather than symptoms and incorporates a mix of contributed data and community surveys to determine the rankings.

  5. WireGuard performance and design advantages

    WireGuard is designed for high performance and simplicity, implemented in less than 4,000 lines of code. Key advantages include:

    • Performance: Outperforms OpenVPN and IPsec in throughput and ping time. It can saturate gigabit Ethernet links without hitting 100% CPU utilization on supported hardware.
    • Efficiency: Uses ChaCha20Poly1305, which is highly efficient in software and resistant to side-channel attacks, making it particularly performant on embedded platforms lacking dedicated AES instructions.
    • Security Architecture: Remains silent to unauthenticated packets and minimizes resource allocations, reducing its visibility and attack surface when deployed on network edges.
    • Low Overhead: Unlike OpenVPN (a user-space application), WireGuard avoids the latency and overhead associated with copying packets between user space and kernel space.

  6. List running processes with ps

    The ps command is used to display information about the currently running processes.
    # List all processes using standard format
ps -elf

# List all processes using BSD-style format
ps -aux

  7. Manually install FrankenPHP binary on Linux

    To manually install FrankenPHP, download the latest binary from GitHub Releases based on your system architecture and move it to /usr/bin/ using the install command.
    # Download the latest binary
wget -q "https://github.com/php/frankenphp/releases/download/$(wget -q -O- 'https://api.github.com/repos/php/frankenphp/releases/latest' | jq -r '.tag_name')/frankenphp-linux-$(uname -m)"

# Install the binary to /usr/bin/
sudo install -v "frankenphp-linux-$(uname -m)" /usr/bin/frankenphp

  8. Configure SOA (Start of Authority) records

    SOA records provide authoritative information about a DNS zone.

    RDATA Fields:

    • MNAME: The <domain-name> of the primary name server for the zone.
    • RNAME: The <domain-name> of the mailbox of the person responsible for the zone.
    • SERIAL: Zone serial number.
    • REFRESH: Time interval for refreshing the zone.
    • RETRY: Time interval for retrying failed refreshes.
    • EXPIRE: Time to expire the zone from secondary caches.
    • MINIMUM: Minimum TTL for the zone.

  9. Understand Botnets and Command and Control (C2) servers

    A botnet is a collection of compromised systems (bots) created by an attacker. These bots are managed by a Command and Control (C2) server, which the attacker uses to send coordinated instructions to the botnet to perform attacks, such as DDoS.

  10. Execute a Social Engineering attack lifecycle

    Social engineering attacks typically follow a four-step process to steal information by exploiting human trust rather than technical vulnerabilities:

    1. Research: Collect information about the target organization via internet searches, scanning, or dumpster diving.
    2. Select Target: Identify a specific employee to target; individuals who are frustrated are often more susceptible.
    3. Relationship: Establish a connection with the target to earn their trust.
    4. Exploit: Use the established trust to collect sensitive information such as usernames and passwords.

  11. Understand the Linux Filesystem Hierarchy Standard (FHS)

    UNIX-based operating systems use a single file system tree starting at the root (/) directory. The Filesystem Hierarchy Standard (FHS) specifies the main directories that must be present and their purposes to simplify the prediction of file locations. While adding additional directories does not violate the standard, placing components in directories other than those described by the FHS is considered a violation.

  12. Audit Cryptographic Implementations for Vulnerabilities

    When reviewing code or architecture for cryptographic failures, check for the following common weaknesses:

    • Cleartext Transmission: Check if data is sent via HTTP, SMTP, or FTP without TLS/STARTTLS, especially in internal traffic between load balancers and back-end systems.
    • Key Management: Look for hard-coded keys in source code, use of default keys, or lack of key rotation.
    • Algorithm Strength: Identify the use of broken or risky algorithms (e.g., MD5, SHA1) or insecure modes of operation (e.g., ECB).
    • Validation: Ensure server certificates and trust chains are properly validated.
    • Entropy: Check if randomness is seeded predictably or if non-cryptographic hash functions are used where cryptographic ones are required.
    • Side Channels: Determine if cryptographic error messages could lead to padding oracle attacks.