51.161.37.168📋 Copy

# INTELLIGENCE BRIEFING: IP 51.161.37.168/32

Classification: Moderate Risk | Date Generated: 2024-01-XX | Intel Source: IPDebrief

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## EXECUTIVE SUMMARY

IP address 51.161.37.168 resolved to a moderate-risk hosting infrastructure operated by Ahrefs Pte Ltd on OVH network. The IP is associated with the ahrefs.net domain and classified as cloud compute infrastructure in Montreal, Quebec, Canada. While no direct threat indicators were present, the subnet exhibits high abuse density with 199 malicious siblings out of 256 total addresses.

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## INFRASTRUCTURE PROFILE

Ownership & Registration

• Organization: Dmytro, Ahrefs Pte Ltd
• ASN: 16276 (OVH)
• CIDR Block: 51.161.37.0/24
• Infrastructure Type: CloudCompute / Hosting Provider
• Service Classification: Firewalled / No Services

Geolocation

• Country: Canada (CA)
• Region: Quebec (QC)
• City: Montreal
• Accuracy Radius: 3,000 km
• Geo Consensus: Confirmed across multiple sources

Network Classification

• Provider: OVH
• Is Cloud: Yes
• Is Hosting: Yes
• Is CDN/VPN/Proxy/Tor: No
• Is Residential/Mobile: No
• Is Bogon: No

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## THREAT INDICATORS

Risk Assessment

• Overall Risk Score: 40/100 (Moderate)
• Abuse Confidence Score: Not applicable
• Provider Score: 0
• Authority Score: 0

Threat Indicators

• Direct Threat Indicators: None
• Known Attacker: No
• Spam Source: No
• Tor Exit Node: No
• Blacklist Count: 0 (direct)
• DNSBL Listed: 1 of 8 total lists

Control Plane Analysis

• Route Stability: Unstable
• Operator Score: 0.2174 (Minimal)
• DNSSEC Validation: Valid
• CAA Records: Present
• Route Changes (30d): 0

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## DOMAIN & DNS ANALYSIS

DNS Records

• PTR Hostname: proxy-ca005-san168.ahrefs.net
• Forward Resolution: Confirmed (1 hostname)
• Domain: ahrefs.net
• Hosted Domains: 0
• Email Authentication: SPF/DMARC not configured

DNSBL Status

• Listed on 1 of 8 threat feeds
• Operator Label: Minimal

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## SERVICE FINGERPRINTING

Port Scanning Results

• Open Ports: None detected
• TLS Certificate: Not present
• HTTP Title/Server Banner: Not present
• Ports Scanned: Multiple ports probed with no services responding
• Connection Status: Firewalled / No Services

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## OBSERVATION HISTORY (22 Total Signals)

Temporal Analysis

• Latest Observation: 2026-06-21T07:56:48 UTC
• Threat Observation Count: 1
• Threat Persistence Days: 0
• Ownership Changes: 0

Historical Signals

• Infrastructure classification consistently identified as cloud hosting
• Geolocation signals showed Canadian origin with variable confidence (0.35-0.90)
• Abuse density classification persisted as "high_abuse" throughout observation period
• Operator score remained at "Minimal" rating
• Multiple port scan events detected from various sources

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## NETWORK RELATIONSHIPS

Connected Entities

• Network: OVH-CUST-281059684 (Primary association)
• DNS Hostnames: proxy-ca005-san168.ahrefs.net
• Total Relationships: 24
• Network Types: Same Network (12), DNS Association (12)

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## SUBNET ANALYSIS (51.161.37.0/24)

Abuse Density Metrics

• Subnet Abuse Density: 0.7773 (High)
• Total Sibling IPs: 256
• Active Siblings: 203
• Threat Siblings: 199
• Inherited Risk Score: 31/100
• Classification: High Abuse

Neighbor Risk Distribution

• High Risk: 0
• Medium Risk: 99
• Low Risk: 1
• Most neighbors exhibited similar risk profiles (Score: 40)

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## RECOMMENDED ACTIONS

Firewall Rules

• Monitor inbound traffic from this subnet for suspicious patterns
• Apply rate limiting for connections to cloud compute services
• Block direct access if internal policy prohibits OVH hosting provider IPs

Monitoring Priorities

• Track DNS query patterns for ahrefs.net domain
• Monitor for new service ports opening on this IP
• Watch for certificate issuance or changes
• Observe connection patterns to related proxy hostnames

Threat Intelligence

• Correlate with other IPs in 51.161.37.0/24 subnet
• Investigate the single DNSBL listing origin
• Monitor for abuse campaigns originating from threat sibling IPs

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## ANALYST NOTES

This IP represents legitimate cloud hosting infrastructure with an ahrefs.net domain association. The primary concern is the high-abuse classification of the parent subnet, indicating 77.7% abuse density. While no direct malicious activity was observed on this specific IP, the neighborhood context suggests elevated risk. SOC teams should monitor for lateral movement patterns within the subnet and consider blocking traffic if organizational policy requires segmentation of hosting provider IPs.

This summary was generated by AI and may contain inaccuracies. Verify critical details independently.