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Introduction:
For decades, cybersecurity has operated on a reactive model—block a malicious domain at your perimeter, but the attacker’s infrastructure remains alive, ready to pivot and strike another victim. The game changes when you stop blocking and start dismantling. TrendAI’s partnership with CleanDNS combines agentic AI workflows with direct registrar/registry integration to remove command-and-control (C2) and delivery domains from the entire internet, not just your network.
Learning Objectives:
- Understand how AI-driven threat intelligence identifies malicious infrastructure before it launches attacks.
- Learn the operational workflow for automated domain takedown via registrar/registry contracts.
- Master practical Linux and Windows commands to investigate, verify, and sinkhole suspicious domains.
You Should Know:
- Investigating Malicious Domains with OSINT and CLI Tools
Before any takedown, you must validate a domain’s reputation and infrastructure. The following commands help you gather evidence similar to TrendAI’s pre-detection phase.
Linux / macOS Commands:
Query DNS records to find A, NS, and MX dig malicious-domain.com A +short dig malicious-domain.com NS +short Check domain age and registrar (requires whois) whois malicious-domain.com | grep -E "Creation Date|Registrar|Name Server" Look for associated IP addresses and ASN nslookup malicious-domain.com host malicious-domain.com Retrieve SSL certificate history (using crt.sh) curl -s "https://crt.sh/?q=%malicious-domain.com&output=json" | jq '.[].name_value' Check if domain is known in threat intelligence feeds (example using AlienVault OTX) curl -s "https://otx.alienvault.com/api/v1/indicators/domain/malicious-domain.com/general" | jq '.pulse_info'
Windows PowerShell (Admin):
Resolve-DnsName malicious-domain.com -Type A
Resolve-DnsName malicious-domain.com -Type NS
Get-DnsClientCache | Where-Object {$_.Entry -like "malicious-domain"}
Step‑by‑step guide:
- Run `dig` or `Resolve-DnsName` to resolve the domain to IPs.
- Use `whois` to identify the registrar and creation date—fresh domains (<30 days) are suspicious.
- Query certificate transparency logs to find associated subdomains.
- Cross-reference with free OTX or MISP feeds to see if already flagged.
-
Automating Threat Intelligence Feeds with Agentic AI Workflows
TrendAI uses machine learning models to tag domains as infostealers, phishing-as-a-service, loaders, or RATs. You can simulate a lightweight automated pipeline using open-source tools and scheduled scripts.
Linux bash script example (cron job):
!/bin/bash Domain monitor script DOMAIN_LIST="/opt/ti/new_domains.txt" LOGFILE="/var/log/ti_alerts.log" while read domain; do Check reputation via VirusTotal API (replace YOUR_API_KEY) curl -s "https://www.virustotal.com/api/v3/domains/$domain" \ -H "x-apikey: YOUR_API_KEY" | jq '.data.attributes.last_analysis_stats' Check if domain resolves to known malicious IP ranges (e.g., C2 IPs) ip=$(dig +short $domain | head -1) if [[ $ip =~ ^(185.|45.|5.) ]]; then Example suspicious netblocks echo "$(date): $domain -> $ip (suspicious)" >> $LOGFILE fi done < $DOMAIN_LIST
Step‑by‑step guide:
- Collect candidate domains from DNS logs, sandbox reports, or public feeds.
- Run the script every 15 minutes via cron (Linux) or Task Scheduler (Windows).
- When a match exceeds confidence threshold (e.g., 2+ engines detect), feed it to an automated takedown API (like CleanDNS or your registrar’s abuse API).
- Remove human validation only after achieving 100% verification over a large sample—TrendAI’s key to speed.
-
Configuring a Local DNS Sinkhole to Block and Log Malicious Domains
While global takedown removes the domain, local sinkhole protects you immediately. Use Pi-hole (Linux) or Windows DNS policies.
Pi-hole (Ubuntu/Debian):
Install Pi-hole curl -sSL https://install.pi-hole.net | bash Add malicious domains to blacklist pihole -b malicious-domain.com another-malicious.net Check real-time query log pihole -t
Windows Server DNS Policy (PowerShell):
Create a zone scope for sinkhole Add-DnsServerZoneScope -Name "SinkholeScope" -ZoneName "malicious-domain.com" Add-DnsServerResourceRecord -ZoneName "malicious-domain.com" -A -Name "@" -IPv4Address "127.0.0.1" -ZoneScope "SinkholeScope"
Step‑by‑step guide:
1. Set up a sinkhole server (e.g., 192.168.1.100).
- For each confirmed malicious domain, add an A record pointing to the sinkhole IP.
- Configure network DHCP to hand out the sinkhole as primary DNS.
- Monitor logs for attempted connections—these indicate compromised hosts.
-
Extracting C2 Infrastructure from Malware Samples Using YARA and Suricata
TrendAI identifies loaders and RATs by analyzing malware network indicators. You can do the same with open-source tools.
YARA rule to detect Lumma Stealer network artifacts:
rule Lumma_C2_String {
strings:
$c2_pattern = /[a-z0-9]{5,}.(ru|top|xyz)/ nocase
$user_agent = "LummaC2" nocase
condition:
$c2_pattern or $user_agent
}
Extract domains from a PCAP using Suricata:
Run Suricata in IDS mode on a pcap suricata -r malware_traffic.pcap -l /var/log/suricata/ Extract all DNS queries tshark -r malware_traffic.pcap -Y "dns.qry.name" -T fields -e dns.qry.name | sort -u
Step‑by‑step guide:
- Capture network traffic from a sandbox executing the malware.
- Run Suricata to alert on known C2 patterns.
- Use `tshark` or `ngrep` to list all contacted domains.
- Hash domains and submit to VT or CleanDNS-like service for takedown.
-
Coordinated Takedown Workflow: From Detection to Registrar Removal
The TrendAI + CleanDNS model removes friction by having direct contractual integration. Here’s how to replicate the process with a registrar that supports API-based abuse reporting.
Example using Namecheap Abuse API (pseudo):
Report domain with evidence JSON curl -X POST https://api.namecheap.com/xml.response \ -d "ApiUser=YOUR_USER" \ -d "ApiKey=YOUR_KEY" \ -d "Command=namecheap.abuse.reportDomain" \ -d "DomainName=malicious-domain.com" \ -d "EvidenceType=phishing" \ -d "EvidenceURL=https://your-evidence-bucket.com/report123.json"
Step‑by‑step guide:
- Gather structured evidence: DNS records, screenshots, malware sample hash, and network logs.
- Verify with 100% confidence—TrendAI uses ML models that have achieved zero false positives over millions of detections.
- Submit via registrar’s abuse API (or via CleanDNS as a proxy).
- Monitor takedown status; most registrars respond within 12–24 hours. For critical C2, escalate to registry (e.g., Verisign for .com).
6. Validating Global Removal Across DNS Resolvers
After a takedown, confirm the domain no longer resolves anywhere. Use distributed queries from multiple vantage points.
Script to check global propagation:
!/bin/bash
Check domain resolution from multiple public DNS resolvers
DOMAIN="malicious-domain.com"
RESOLVERS=("8.8.8.8" "1.1.1.1" "9.9.9.9" "208.67.222.222")
for resolver in "${RESOLVERS[@]}"; do
result=$(dig @$resolver $DOMAIN A +short)
echo "$resolver : $result"
done
Using RIPE Atlas (free probes):
Via ripe-atlas CLI atlas-resolve -p 1000 -t A $DOMAIN
Step‑by‑step guide:
- After receiving takedown confirmation, wait 30 minutes (average CleanDNS verification time).
- Run the multi-resolver script. All should return `NXDOMAIN` or sinkhole IP.
- If any resolver still returns the original IP, escalate to the registry.
7. Hardening Cloud Environments Against Residual C2 Communication
Even after domain removal, attacker infrastructure may persist via IP addresses. Implement egress filtering in AWS/Azure/GCP.
AWS Network ACL to block known C2 IPs (Terraform):
resource "aws_network_acl_rule" "block_c2" {
network_acl_id = aws_network_acl.main.id
rule_number = 100
egress = true
protocol = "-1"
rule_action = "deny"
cidr_block = "185.130.5.0/24" Example C2 netblock
from_port = 0
to_port = 0
}
Step‑by‑step guide:
- Extract IP addresses from the removed domains’ historical A records.
- Create deny rules for those IPs at the network layer.
- Monitor VPC flow logs for any attempts to those IPs—indicating persistent malware.
What Undercode Say:
- Key Takeaway 1: The shift from blocking to dismantling attacker infrastructure is a maturity leap. Coordinated registrar integration with 100% verified intelligence removes the attack surface globally, not just at your perimeter.
- Key Takeaway 2: Speed matters—12 minutes to protect customers, 2.5 days to erase a domain from the internet. This compresses the attacker’s ROI to near zero because their C2 becomes unusable before they can weaponize it at scale.
Analysis: TrendAI’s model solves the false-positive dilemma that has historically prevented automated takedowns. By achieving a perfect verification rate across millions of ML-tagged domains, they can remove the human-in-the-loop bottleneck. For security teams, this means you can now trust an automated pipeline to feed domains directly to registrars without fear of taking down legitimate sites. The remaining challenge is jurisdiction—some registrars in hostile nations will ignore abuse requests. Future partnerships must pressure ccTLDs and ICANN to adopt similar contractual obligations.
Prediction:
Within 18 months, major cloud providers and MSSPs will adopt similar “infrastructure removal” SLAs as a standard service tier. Attackers will respond by moving to decentralized infrastructure—bulletproof hosting, fast-flux networks, and blockchain-based domains (e.g., Handshake). This will force threat intelligence to evolve toward AI-driven prediction of attack infrastructure before domains are even registered, using pre-crime analytics on registrant patterns and DNS tunneling behavior. The cat-and-mouse game will shift left—into the domain registration process itself.
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IT/Security Reporter URL:
Reported By: Jpcastro During – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
