51.161.37.199📋 Copy

## INTELLIGENCE BRIEFING: 51.161.37.199/32

Classification: MODERATE RISK

Date: 2026-06-15

Analyst: IPDebrief Intelligence Unit

Target: 51.161.37.199

---

EXECUTIVE SUMMARY

IP address 51.161.37.199 was assessed as a moderate-risk endpoint (Risk Score: 40/100) operating within an OVH CloudCompute infrastructure. The IP is registered to "Dmytro, Ahrefs Pte Ltd" under ASN 16276 and belongs to CIDR block 51.161.37.0/24. Despite moderate individual risk scoring, the parent subnet exhibits high abuse density (0.7422) with 190 of 256 total IPs flagged as threats, indicating contextual risk elevation.

---

INFRASTRUCTURE PROFILE

Network Ownership:

• ASN: 16276
• Organization: Dmytro, Ahrefs Pte Ltd
• Network Name: OVH-CUST-281059684
• RIR: ARIN
• Infrastructure Type: CloudCompute
• Hosting Status: Active

Geolocation:

• Country: Canada (CA)
• City: Singapore (data inconsistency detected)
• Accuracy Radius: 3000km
• RTT Validation: FAILED (Observed: 27ms; Minimum Possible for distance: 121.6ms)
• GeoPlausible: FALSE

DNS Resolution:

• PTR Hostname: proxy-ca005-san199.ahrefs.net
• Domain: ahrefs.net
• Forward Resolution: Confirmed (1 hostname)
• Email Authentication: SPF/DMARC records absent

---

THREAT INDICATORS

Direct Threats:

• Abuse Confidence Score: NULL
• Known Attacker: FALSE
• Spam Source: FALSE
• Tor Exit Node: FALSE
• Blacklist Count: 0
• Known Campaigns: None

DNS Blacklist Status:

• Listed on 1 DNSBL with high severity
• Total DNSBL lists: 8
• Operator Score: 0.2174 (Minimal)

Observed Threat Signals:

• 19 total observations recorded
• Most recent signal: 2026-06-15 (subnet abuse classification)
• Historical blacklist detection: 1 listing with high severity
• Threat persistence days: 0

---

SUBNET CONTEXTUAL ANALYSIS

Parent Subnet: 51.161.37.0/24

• Classification: HIGH ABUSE
• Abuse Density: 0.7422 (74.2%)
• Total Siblings: 256
• Active Siblings: 198
• Threat Siblings: 190
• Inherited Risk: 29/100

Risk distribution across neighboring IPs indicates 99 medium-risk and 1 low-risk endpoint, with no high-risk classifications directly attributed to 51.161.37.199.

---

OBSERVATION HISTORY

The IP has generated 19 observations across multiple signal types:

• 2026-06-15 15:40: Subnet abuse classification recorded (abuse density: 0.7422)
• 2026-06-15 15:33: Operator score assessment (0.2174) with DNSSEC validation
• 2026-06-09 18:30: Geolocation data (country: CA) with confidence 0.18
• 2026-06-09 18:27: DNSBL listing confirmed (8 total lists, 1 active, high severity)

No persistent malicious activity detected (threatPersistenceDays: 0).

---

NETWORK RELATIONSHIPS

The IP maintains 32 relationships, predominantly same-network associations with OVH-CUST-281059684. No cross-organizational or cross-subnet relationships beyond the parent cloud infrastructure block were identified.

---

RECOMMENDED ACTIONS

Immediate Mitigation:

• iptables: `iptables -A INPUT -s 51.161.37.199 -j DROP`
• nftables: `nft add rule inet filter input ip saddr 51.161.37.199 drop`
• nginx: `deny 51.161.37.199;`
• pfSense: `51.161.37.199/32`
• Cloudflare WAF: Block expression `ip.src eq 51.161.37.199`
• AWS WAF: Address `51.161.37.199/32`

---

ANALYST NOTES

1. Subnet Contamination Risk: The parent subnet 51.161.37.0/24 demonstrates 74.2% abuse density with 190 threat-flagged siblings. While 51.161.37.199 lacks direct threat indicators, the contextual environment warrants heightened scrutiny.

2. Geolocation Discrepancy: RTT measurements indicate significant data inconsistency (observed 27ms vs. minimum 121.6ms for Canada-Singapore distance). This suggests geolocation data may be unreliable for operational purposes.

3. Infrastructure Classification: The endpoint is firewalled with no active services detected, reducing immediate exploitation risk.

4. Blocking Justification: Despite moderate individual risk scoring, the high-abuse subnet context combined with DNSBL listings supports preventive blocking measures.

---

End of Briefing

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