Welcome back, aspiring cyberwarriors!
In the ever-evolving landscape of cybersecurity, new tools and approaches are constantly emerging to combat the growing sophistication of cyber threats. One such innovative solution is CrowdSec, a free and open-source security automation tool that leverages the power of crowdsourcing to detect and mitigate cyber attacks. This article delves into the history of threat intelligence and explores how CrowdSec addresses modern cybersecurity challenges. It also includes a guide for installation and setup, along with an analysis of its benefits and potential drawbacks.
Evolution of Threat Intelligence
Threat intelligence has advanced significantly since the early days of cybersecurity. In the past, organizations primarily relied on signature-based detection methods, which involved identifying known malicious patterns in network traffic or system behavior. While effective against recognized threats, this approach struggled to keep pace with the rapid evolution of cyberattacks.
As cyber threats grew more sophisticated, the cybersecurity community recognized the need for more proactive and adaptive approaches. This realization led to the development of behavioral analysis, machine learning-based detection, and, eventually, collaborative threat intelligence platforms.
The idea of sharing threat information among organizations started to gain popularity in the early 2000s. Information Sharing and Analysis Centers (ISACs) were created to help share threat data within specific industries. However, these early efforts often faced challenges with data standardization and real-time sharing.
The rise of cloud computing and big data analytics marked a new era in threat intelligence. Platforms capable of collecting, analyzing, and sharing large volumes of threat data in real-time appeared, enabling organizations to stay ahead of evolving threats.
What is CrowdSec
CrowdSec is a security tool designed to help protect servers and applications from cyberattacks. It works by analyzing logs from your systems to detect suspicious activity, such as brute-force attempts, and then takes action to block or prevent those threats.
CrowdSec’s uniqueness is its “crowd-powered” approach. When it detects a potential threat on one system, it shares that information with a global community of other users. This way, everyone using CrowdSec benefits from the collective knowledge of cyberattacks happening around the world, making it more effective at spotting and stopping threats.
How Does It Work
CrowdSec parse logs to detect an attack behavior. If an attack pattern is recognized, it will raise an alert and optionally remediate the attack locally. When an attack is detected, the users can choose to share the information with the community. In return, the users benefit from information shared by other community members, which leads to stronger protection, as attackers are banned before their attacks are perpetrated.
Examples Of Detected Behaviour’s
CrowdSec is designed to detect and mitigate a variety of cyber threats and attacks. The image above illustrates some common attack types that CrowdSec can help identify.
Problems CrowdSec Solves
Information Silos: Traditional security methods often keep valuable threat information locked within individual organizations.
Resource Constraints: Small and medium-sized businesses often lack the resources for comprehensive security solutions or dedicated security teams.
Reactive Security: Many security tools focus on responding to known threats instead of proactively finding new ones.
False Positives: Sensitive security systems can produce many false alerts, leading to alert fatigue and the risk of missing real threats.
CrowdSec addresses these issues by creating a community-driven security network. When a threat is detected, CrowdSec blocks the malicious IP address locally and shares this information with the entire CrowdSec community.
Installing
First, we need to install the Security Engine from the CrowdSec repositories, which provides access to the latest packages of CrowdSec and its bouncers. This can be done using the following command:
kali> curl -s https://packagecloud.io/install/repositories/crowdsec/crowdsec/script.deb.sh | sudo bash
But in Kali Linux, you will see the following error:
Therefore, for the convenience of testing, I will use an Ubuntu server in AWS.
Next, we need to install CrowdSec using the following command:
server> sudo apt install crowdsec
CrowdSec Collections
In CrowdSec, collections refer to bundles or sets of pre-configured security rules, parsers, and scenarios tailored for specific use cases or environments. These collections simplify the setup process by offering a curated combination of resources that address particular needs. Examples include configurations for SSH, Nginx, and various other applications and services.
Since I have Apache and SSH installed, CrowdSec automatically installs the relevant collections. To view the list of enabled collections, use the following command:
server> sudo cscli hub list
Remediation Components
Security Engine by itself is a detection engine, it will not block anything. So, we need to install Remediation Components ("bouncers") to enforce decisions.
In this example let’s install crowdsec-firewall-bouncer:
kali> sudo apt install crowdsec-firewall-bouncer crowdsec-firewall-bouncer-nftables
The setup is ready and now we can test the effectiveness.
Brute Force Attack Simulation
Before we begin, let’s view the current decision list on the CrowdSec server:
kali> sudo cscli decision list
After that, I’ll attempt to log in to the server via SSH using an incorrect password. After repeating this a few times, I am now banned.
If you want, you can unblock the IP again with cscli decisions delete command after which you will be able to login.
server> sudo cscli decisions delete -i <ip>
Dashboard
You can view these details through the web UI. To do this, you need to sign up at app.crowdsec.net. On the Security Engine page, you will find an option to enroll your engine, making it available on the Dashboard.
server> sudo cscli console enroll -e context <id>
Copy and paste in your server with CrowdSec server. Then you will have a promt to accept or deny the request on the Dashboard.
After enrolling, you need to restart CrowdSec for the engine to begin reporting to the Dashboard.
Benefits and Drawbacks of CrowdSec
Like any security solution, CrowdSec comes with its own set of advantages and potential limitations.
By leveraging the collective knowledge of its user base, CrowdSec can quickly identify and respond to new threats, often faster than traditional, centralized threat intelligence platforms.
As an open-source solution, CrowdSec is free to use, making it accessible to organizations of all sizes, including small businesses that may not have the budget for enterprise security solutions.
The crowdsourced approach helps in reducing false positives, as threats are verified across multiple instances before being flagged.
Rather than relying solely on known threat signatures, CrowdSec can detect and respond to new attack patterns based on behavior analysis.
The effectiveness of CrowdSec relies heavily on active community participation. In niche environments or during the early stages of adoption, this could potentially limit its effectiveness.
Some organizations may have reservations about sharing security events, even anonymously, due to regulatory or internal policy constraints.
Currently, CrowdSec primarily focuses on IP-based threat mitigation, which may not be sufficient for all types of sophisticated attacks.
CrowdSec's real-time threat sharing requires a constant internet connection, which might not be feasible in air-gapped or highly restricted network environments.
Summary
As cyber threats continue to evolve in complexity and scale, solutions like CrowdSec that leverage collective intelligence and foster collaboration within the security community are likely to play an increasingly important role in our digital defense strategies.