54.39.136.51📋 Copy

# IP INTELLIGENCE BRIEFING: 54.39.136.51

Classification: Moderate Risk | Date: 2026-06-19

## Executive Summary

IP 54.39.136.51 presents a moderate risk profile (Risk Score: 40) within a high-abuse density subnet. The address resolves to OVH cloud infrastructure hosting an Ahrefs-branded proxy service in Beaucharnois, Quebec, Canada. While the IP itself shows no active malicious indicators, its subnet demonstrates elevated abuse activity requiring defensive posture consideration.

## Technical Profile

Ownership & Infrastructure

• ASN: 16276 (OVH)
• Organization: Dmytro, Ahrefs Pte Ltd
• Netname: OVH-CUST-281059681
• CIDR Block: 54.39.136.0/24
• Location: Beauharnois, QC, CA (3000km accuracy radius)
• Classification: Cloud Computing / Hosting Infrastructure

DNS & Service Status

• PTR Record: proxy-ca002-san51.ahrefs.net
• Forward Resolution: proxy-ca002-san51.ahrefs.net (ahrefs.net)
• Open Ports: None detected
• Network Role: Firewalled / No Services
• Reverse DNS: Confirmed

## Threat Assessment

Current Indicators

• Risk Score: 40/100 (Moderate)
• Abuse Confidence Score: Not available
• Blacklist Status: 0 blacklists, 1 DNSBL listing (of 8 total)
• Threat Feeds: No active indicators
• Campaign Likelihood: None
• Tor/VPN/Proxy: Not classified as such

Control Plane

• Route Stability: Not stable (route changes detected)
• RPKI State: Not available
• DNSSEC: Valid
• Operator Score: 0.2174 (Minimal)

## Subnet Neighborhood Analysis

54.39.136.0/24 Assessment

• Abuse Density: 0.5041 (High abuse classification)
• Total Siblings: 246 IPs
• Active Siblings: 116
• Threat Siblings: 124
• Inherited Risk Score: 20

Risk Distribution: 0 High / 99 Medium / 1 Low risk neighbors observed. The subnet exhibits concentrated activity with approximately 50% abuse density, indicating coordinated infrastructure usage typical of cloud hosting environments.

## Historical Observation

Signal Timeline (24 observations)

• Most Recent: 2026-06-19 06:11:25 UTC
• Provider Classification: Consistent OVH attribution
• Threat Persistence: 0 days (not persistently malicious)
• Ownership Changes: None recorded
• Geolocation: Consistent Canada (QC) attribution with moderate confidence (0.35)

The IP demonstrates stable infrastructure characteristics with no significant reputation degradation over the observation period.

## Relationship Graph

Connected Entities (51 relationships)

• Primary: OVH-CUST-281059681 network (multiple same-network links)
• Classification: Cloud infrastructure relationships
• No external malicious entity connections identified

## Recommended Actions

Immediate Mitigation

• Block traffic at perimeter firewalls using provided rules below
• Configure WAF rules to reject connections from this IP
• Monitor for lateral movement attempts from related IPs in the subnet

Firewall Rules

```bash

# iptables

iptables -A INPUT -s 54.39.136.51 -j DROP

# nftables

nft add rule inet filter input ip saddr 54.39.136.51 drop

# nginx

deny 54.39.136.51;

# pfSense

54.39.136.51/32

# Cloudflare WAF

{"description": "Block 54.39.136.51 — IPDebrief risk score 40", "action": "block", "filter": {"expression": "ip.src eq 54.39.136.51"}}

# AWS WAF

{"Addresses": ["54.39.136.51/32"], "Description": "IPDebrief risk 40"}

```

Extended Mitigation

• Consider blocking entire /24 subnet (54.39.136.0/24) given 50% abuse density
• Monitor for connection patterns from related IPs in the 124 threat-sibling IPs
• Implement rate limiting if blocking individual IPs proves insufficient

## Intelligence Notes

This IP represents legitimate cloud hosting infrastructure (OVH) with Ahrefs branding. The moderate risk score derives primarily from subnet-level abuse activity rather than direct malicious indicators. The high-abuse density environment suggests this subnet may host legitimate services alongside potentially compromised endpoints. Defensive posture should balance between blocking individual threats and monitoring subnet-level patterns.

Threat Level: MODERATE

Confidence: HIGH

Action Required: FIREWALL RULE IMPLEMENTATION

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