51.161.37.253📋 Copy

## IP Intelligence Briefing: 51.161.37.253/32

Executive Summary

IP 51.161.37.253 is a moderate-risk (score: 40) cloud hosting address associated with Ahrefs infrastructure. While the IP itself shows no direct threat indicators, it resides within a high-abuse-density subnet (51.161.37.0/24) with 71.88% abuse density and 184 threat-sibling IPs out of 256 total addresses. SOC analysts should monitor this IP for lateral movement patterns and apply defensive controls due to neighborhood risk exposure.

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Technical Profile

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Geographic Analysis

• Reported Location: Singapore (with CA country code inconsistency)
• Geo Consensus: Verified (1 source)
• Accuracy Radius: 3000 km
• Note: Geographic data shows significant uncertainty; location claims should not be used for definitive threat attribution.

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DNS & Network Services

• PTR Hostname: proxy-ca005-san253.ahrefs.net
• Resolved Domain: ahrefs.net
• Forward Resolution: 1 hostname
• DNSSEC: Valid
• CAA Records: Present
• Open Ports: None detected
• HTTP Services: None (firewalled)
• TLS Certificate: None

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Threat Indicators

• Known Attacker: No
• Spam Source: No
• Tor Exit Node: No
• Blacklist Count: 0
• DNSBL Lists: 1 of 8 total lists
• Known Campaigns: None detected
• Abuse Confidence: Not quantified

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Neighborhood Assessment (51.161.37.0/24)

• Subnet Size: 256 IPs
• Active Siblings: 198
• Threat Siblings: 184
• Abuse Density: 71.88% (High)
• Inherited Risk: 28
• Risk Distribution: 99 medium-risk, 1 low-risk, 0 high-risk
• Classification: High Abuse Subnet

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Historical Observations

• Total Signals: 17 observations
• Recent Activity: Signals observed as of 2026-06-20
• Provider Stability: Minimal changes (0 ownership changes)
• Threat Persistence: No persistent malicious behavior detected
• Route Stability: Unstable (isRouteStable: false)

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Relationships

• Primary Connection: Same network (OVH-CUST-281059684) - 37 relationship entries
• Network Classification: Consistent cloud hosting infrastructure
• Correlated IPs: 0 direct campaign correlations

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Recommended Actions

Based on the high-abuse neighborhood context and moderate risk profile:

1. Firewall Rules: Implement rate limiting for this /24 subnet; consider blocking if legitimate Ahrefs traffic is not expected

2. Monitoring: Enable traffic logging for this IP and its neighbors to detect potential lateral movement

3. Threat Detection: Alert on connection attempts from this subnet, particularly to sensitive internal resources

4. Geolocation Validation: Correlate with known Ahrefs infrastructure locations; geo-discrepancies warrant investigation

5. DNSBL Monitoring: Monitor for new blacklist additions; currently listed on 1 of 8 DNSBL lists

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Intelligence Assessment

This IP represents an infrastructure node within a known hosting provider's customer block. While the IP itself lacks direct threat indicators, the high-density abuse environment of its subnet warrants defensive posturing. The presence of 184 threat-sibling IPs suggests coordinated abuse patterns within the /24. SOC teams should treat this IP as part of a broader threat landscape and implement perimeter controls accordingly.

Classification: MONITOR (Elevated due to neighborhood risk)

Priority: Medium

Confidence: 0.85 (based on historical signal confidence)

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