51.161.65.21📋 Copy

# IP INTELLIGENCE BRIEFING

Target: 51.161.65.21/32

Date: Current Analysis Cycle

Classification: Moderate Risk Cloud Infrastructure IP

---

## EXECUTIVE SUMMARY

IP 51.161.65.21 is a cloud hosting infrastructure address associated with OVH SAS (ASN 16276) under customer identifier OVH-CUST-281059690. The IP resolves to the ahrefs.net domain (proxy-ca011-san21.ahrefs.net), indicating legitimate web infrastructure usage. No active threat indicators, blacklists, or campaign correlations were detected. However, geolocation data shows implausible location reporting, and the IP resides within a high-abuse-density subnet (0.7266 abuse density).

---

## OWNERSHIP & NETWORK CLASSIFICATION

---

## RISK PROFILE & THREAT INDICATORS

Risk Score: 50 (Moderate Risk)

Abuse Confidence Score: Not reported

Blacklist Count: 0

Known Campaigns: None

Threat Indicators

• Tor Exit Node: No
• Known Attacker: No
• Spam Source: No
• DNSBL Listings: 0 (total 8 DNSBLs checked)

Control Plane Analysis

• BGP Prefix: 51.161.0.0/17
• Route Stability: False (route changes observed in past 30 days)
• RPKI State: Not reported
• Operator Score: 0.2174 (Minimal)

---

## GEOLOCATION ANALYSIS

Reported Location: Singapore, CA (Country Code: CA)

Validation Status: INVALID

GeoValidation Violation

• Claimed Distance: 6082 km
• Observed RTT: 27.0 ms
• Minimum Possible RTT: 121.6 ms for 6082 km
• Status: RTT violation indicates geolocation spoofing or misattribution

Historical Observations:

• 26 total signal observations recorded
• One observation (2026-06-19) reported Montreal, QC location
• Multiple probes show inconsistent geolocation data

---

## NEIGHBORHOOD INTELLIGENCE

Subnet: 51.161.65.0/24

Total Siblings: 256

Active Siblings: 212

Threat Siblings: 186

Abuse Density: 0.7266 (High Abuse Classification)

Inherited Risk: 29

Risk Distribution in Subnet

• High Risk: 0
• Medium Risk: 98
• Low Risk: 2

Sample Neighbor Risk Scores:

• 51.161.65.0: Risk 40, Authority 50
• 51.161.65.1: Risk 40, Authority 50
• 51.161.65.2: Risk 50, Authority 50
• 51.161.65.3: Risk 40, Authority 50
• 51.161.65.4: Risk 40, Authority 50

---

## NETWORK SERVICES & FINGERPRINTING

Connection Type: Firewalled / No Services

---

## RELATIONSHIP GRAPH

The IP has 50 recorded relationships, predominantly "Same Network" type associations linking to OVH-CUST-281059690 network identifier. No external hostname, organization, or certificate relationships beyond the OVH network classification were identified.

---

## OBSERVATION HISTORY (26 Signals)

Recent historical activity indicates:

• 2026-06-19: Threat signal observed via Alienvault OTX
• 2026-06-18: High-abuse subnet classification confirmed
• 2026-06-18: Geovalidation violation flagged
• 2026-06-18: Operator score computed at 0.2174 (Minimal)

Threat Persistence: 0 days (not persistently malicious)

Ownership Changes: 0

---

## RECOMMENDED ACTIONS

Firewall Rules (Block Recommended)

iptables:

```bash

iptables -A INPUT -s 51.161.65.21 -j DROP

```

nftables:

```bash

nft add rule inet filter input ip saddr 51.161.65.21 drop

```

nginx:

```nginx

deny 51.161.65.21;

```

Cloudflare WAF:

```json

{

"description": "Block 51.161.65.21 — IPDebrief risk score 50",

"action": "block",

"filter": {

"expression": "ip.src eq 51.161.65.21"

}

}

```

AWS WAF:

```json

{

"Addresses": ["51.161.65.21/32"],

"Description": "IPDebrief risk 50"

}

```

---

## ANALYST NOTES

1. Geolocation Discrepancy: The IP reports Singapore location but observed RTT of 27ms contradicts the 6082km distance to claimed location. This pattern suggests either IP spoofing or OVH's geolocation database misattribution. Historical data shows Montreal observations.

2. Subnet Context: The parent subnet (51.161.65.0/24) exhibits high abuse density (0.7266) with 186 of

the total sibling population were classified as threat siblings.

3. **Service Availability

Service Availability: No open ports, TLS certificates, or HTTP services detected on the target. The connection status is reported as "Firewalled / No Services."

4. DNS Configuration: DNSSEC is valid with CAA records present. SPF and DMARC authentication records are absent.

5. Actionable Intelligence: Block the IP at perimeter controls. Monitor for activity from subnet 51.161.65.0/24 due to high abuse density. Investigate any lateral movement attempts within the OVH network if correlated with other incidents.

---

## CONCLUSION

The IP 51.161.65.21 presents a moderate risk profile with no direct threat indicators. However, the high-abuse-density subnet and geolocation inconsistencies warrant defensive monitoring. Implement recommended blocking rules and maintain vigilance for related network activity.

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