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Introduction:
A new wave of Fortinet brute-force attacks, originating from GoDaddy infrastructure, has been observed targeting networks globally. This campaign, with a 0/95 detection score on VirusTotal, highlights the evolving tactics of threat actors leveraging reputable services to bypass traditional security defenses.
Learning Objectives:
- Understand the mechanics of a Fortinet brute-force attack and how to identify its indicators of compromise (IoCs).
- Learn essential commands to detect, analyze, and mitigate such credential-based attacks on your network.
- Develop a proactive defense strategy using logging, network monitoring, and system hardening techniques.
You Should Know:
1. Identifying Suspicious Login Activity
Fortinet devices and Windows servers are primary targets. The first step is to audit authentication logs.
Linux (Check Auth Logs) sudo grep "Failed password" /var/log/auth.log sudo grep "Accepted password" /var/log/auth.log Windows (Query Security Log for Failed Logins) Get-EventLog -LogName Security -InstanceId 4625 -Newest 50 FortiGate (CLI command to show admin login attempts) execute log filter category 3 execute log display
Step-by-step guide: On a Linux system, the `grep` commands will filter the authentication log for failed and successful password attempts, helping you identify brute-force patterns. In Windows, the `Get-EventLog` PowerShell cmdlet retrieves the most recent 50 failed login events (Event ID 4625). On a FortiGate device, the CLI commands filter and display the event log for user activity, allowing you to see login attempts in real-time.
2. Analyzing Network Connections
Detect unexpected outbound connections from your network to potential C2 servers.
Linux (List active network connections)
netstat -tunap
ss -tunp
Windows (List active network connections)
netstat -ano
Get-NetTCPConnection | Where-Object {$_.State -eq "Established"}
Check for connections to common hosting IPs (e.g., GoDaddy ASN)
whois <IP_ADDRESS>
Step-by-step guide: The `netstat` and `ss` commands on Linux provide a list of all active TCP/UDP connections along with the associated process ID (PID). On Windows, `netstat -ano` and the PowerShell `Get-NetTCPConnection` cmdlet perform a similar function. Cross-referencing suspicious external IPs with a WHOIS lookup can reveal if they belong to a hosting provider like GoDaddy, a common tactic for attackers.
3. Leveraging Packet Capture for Deep Inspection
When automated tools fail, manual packet analysis is crucial.
Linux (tcpdump to capture packets) sudo tcpdump -i any -w fortinet_bruteforce.pcap host <SUSPECT_IP> Analyze with Wireshark (Filter for authentication traffic) ftp || http.request.method == "POST" || ssh
Step-by-step guide: Use `tcpdump` to capture all traffic to and from a suspect IP address, saving it to a file. Open this file in Wireshark and use the display filter shown to isolate protocols commonly used in brute-force attacks, such as FTP, HTTP POST requests (for web logins), and SSH. This can reveal cleartext credentials or the attack pattern.
4. Implementing Fail2ban for Automated Defense
Fail2ban scans log files and bans IPs that show malicious signs.
Install Fail2ban (Ubuntu/Debian) sudo apt update && sudo apt install fail2ban Configure a custom jail for SSH (/etc/fail2ban/jail.local) [bash] enabled = true port = ssh logpath = /var/log/auth.log maxretry = 3 bantime = 3600 Start and enable Fail2ban sudo systemctl enable fail2ban && sudo systemctl start fail2ban
Step-by-step guide: After installation, create a custom jail configuration. The example above protects the SSH service. It monitors /var/log/auth.log, bans any IP after 3 failed attempts (maxretry), and maintains the ban for 1 hour (bantime). This automatically mitigates brute-force attempts.
5. Hardening FortiGate Configurations
Proactively secure your Fortinet devices against these attacks.
FortiGate CLI Commands config system admin edit "admin" set password <COMPLEX_PASSWORD> set trusthost1 <YOUR_IP_ADDRESS>/32 next end Enable brute-force detection and lockout config user setting set auth-blacklist-threshold 5 set auth-blacklist-time 300 end Set a login banner config system global set admin-login-banner enable end
Step-by-step guide: These commands enhance security by restricting the admin account to log in only from a specific, trusted IP address (trusthost1). They also configure the system to blacklist an IP for 5 minutes after 5 failed login attempts and enable a login banner, which can serve as a legal warning.
6. PowerShell Incident Response Script
Automate the collection of security events on a Windows system.
PowerShell script to gather login events
$Events = Get-WinEvent -FilterHashtable @{LogName='Security'; ID=4625,4624} -MaxEvents 100
$Events | Select-Object TimeCreated, Id, LevelDisplayName, Message | Export-Csv -Path "C:\Temp\LogonEvents.csv" -NoTypeInformation
Query for specific event ID details
Get-WinEvent -FilterHashtable @{LogName='Security'; ID=4625} | Where-Object {$_.Message -like "Source Network Address:10.0.0."} | Format-List
Step-by-step guide: This script queries the Windows Security log for the 100 most recent failed (4625) and successful (4624) logon events and exports them to a CSV file for analysis. The second command filters failed logons from a specific source network, helping to pinpoint an attack from a particular subnet.
7. Cloud Security Monitoring with AWS CLI
If the attack originates from cloud infrastructure, cloud trails are vital.
Check AWS CloudTrail for suspicious activity aws cloudtrail lookup-events --lookup-attributes AttributeKey=EventName,AttributeValue=ConsoleLogin --region us-east-1 Check for API calls from a specific IP aws cloudtrail lookup-events --lookup-attributes AttributeKey=SourceIPAddress,AttributeValue=54.210.12.34
Step-by-step guide: These AWS CLI commands query CloudTrail logs. The first looks for console login events, while the second filters all events from a specific source IP address. This is critical for tracing back an attack to its source within a cloud environment like AWS, which may be used as a launchpad.
What Undercode Say:
- The Obfuscation Economy is Thriving: The use of legitimate services like GoDaddy to host attack infrastructure, combined with a 0/95 VirusTotal score, signals a mature “obfuscation economy.” Attackers are increasingly operating from within trusted domains, forcing defenders to rely more on behavioral analysis than static IoCs.
- Automation is the New Perimeter: The comment from the original post, “il faut que j’automatise ces posts” (I need to automate these posts), is a microcosm of the entire cybersecurity landscape. The speed and scale of modern threats mean manual intervention is insufficient. Defensive automation, like the Fail2ban and PowerShell scripts outlined, is no longer optional but a core component of a resilient security posture.
This campaign is a stark reminder that the security perimeter is now defined by identity and behavior. As attackers automate their workflows, so must we. The low detection score is not a failure of antivirus but a call to arms for deeper, context-aware monitoring that looks beyond known-bad signatures to anomalous sequences of action, such as rapid, global login attempts from cloud IP space.
Prediction:
The success of this low-detection, high-volume attack from a trusted service provider will catalyze a shift in the cybercriminal underground. We predict a surge in “bulletproof hosting” services that specifically market their ability to evade automated reputation-based blocking. This will force a fundamental change in defensive technologies, pushing the industry towards widespread adoption of AI-driven User and Entity Behavior Analytics (UEBA) and Deception Technology (as hinted at by the original author’s expertise) to generate high-fidelity, contextual threat intelligence from within the noise of everyday network traffic.
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IT/Security Reporter URL:
Reported By: UgcPost 7381962650294861824 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
