51.161.37.88📋 Copy

# Intelligence Briefing: 51.161.37.88/32

Classification: Moderate Risk | Report Date: Current | Source: IPDebrief Intelligence Platform

---

## Executive Summary

IP 51.161.37.88 is a cloud-hosted address assigned to OVH network customer OVH-CUST-281059684 under ASN 16276. The IP resolves to the ahrefs.net domain infrastructure and resides within a high-abuse-density subnet (51.161.37.0/24). While the IP itself shows moderate risk scoring (40/100) with no active threat indicators, the neighborhood exhibits elevated abuse density (0.7383), with 189 of 256 sibling IPs flagged as threats.

---

## Network Identity & Ownership

The IP is registered under an OVH hosting customer account. DNS resolution confirms association with ahrefs.net, a legitimate SEO analytics platform. No open ports were detected, indicating the host is either firewalled or inactive.

---

## Risk Assessment

Overall Risk Score: 40/100 (Moderate Risk)

Threat Indicators:

• Not a Tor exit node
• Not a known attacker
• Not a spam source
• Blacklist count: 0
• DNSBL listed: 1 of 8 total lists

Control Plane Data:

• Origin ASN: 16276
• BGP Prefix: 51.161.0.0/17
• Operator Score: 0.2174 (Minimal)
• Route Stability: False

---

## Neighborhood Analysis

Subnet: 51.161.37.0/24

The /24 subnet demonstrates significant abuse concentration. Nearly 74% of the subnet is classified as high abuse, with 189 IPs actively flagged as threats. This contextualizes the IP's moderate risk score within a hostile network environment.

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## Geolocation Validation

Discrepancy Detected: Reported geolocation shows Singapore with 3,000km accuracy radius, but RTT validation indicates a violation. Measured RTT (26ms) falls below the minimum possible RTT (121.6ms) for the reported 6,082km distance, suggesting geolocation data may be inaccurate or the IP may be using anycast/mirror infrastructure.

---

## Historical Signal Observations

24 observations recorded. Key historical signals include:

• Cloud infrastructure classification (OVH provider)
• ahrefs.net domain resolution
• High abuse subnet classification
• DNS and routing signal stability

No persistent malicious behavior detected over the observation window.

---

## Recommended Actions

Immediate Mitigation:

```bash

# iptables

iptables -A INPUT -s 51.161.37.88 -j DROP

# nftables

nft add rule inet filter input ip saddr 51.161.37.88 drop

# nginx

deny 51.161.37.88;

# pfSense

51.161.37.88/32

# Cloudflare WAF

{

"description": "Block 51.161.37.88 — IPDebrief risk score 40",

"action": "block",

"filter": {"expression": "ip.src eq 51.161.37.88"}

}

# AWS WAF

{

"Addresses": ["51.161.37.88/32"],

"Description": "IPDebrief risk 40"

}

```

Analysis Note: While the IP carries a moderate risk score with no direct threat indicators, the high-abuse-density neighborhood and subnet-level threat concentration warrant defensive blocking. The ahrefs.net association suggests this may be infrastructure for a legitimate SEO service, but the elevated neighborhood risk suggests compromised or abused accounts within the same hosting block.

---

## Intelligence Conclusion

IP 51.161.37.88 represents a moderate-risk address within a high-abuse-density OVH hosting subnet. The IP resolves to legitimate ahrefs.net infrastructure but operates in a network environment where 73.8% of sibling IPs are classified as abusive. No active threat indicators are present against this specific IP. SOC teams should weigh the subnet-level risk against the legitimate service association when determining blocking policies. Consider implementing subnet-level monitoring for 51.161.37.0/24 to detect coordinated abuse campaigns.

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