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Anthropic-Cybersecurity-Skills/skills/hunting-for-dns-based-persistence/SKILL.md
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mukul975 efca3ec611 feat: add NIST CSF 2.0 nist_csf field to all 754 cybersecurity skills
Mapped every skill to NIST CSF 2.0 subcategory IDs (GV/ID/PR/DE/RS/RC functions)
based on subdomain and content analysis. Restores 11 skills corrupted during
prior rebase, re-enriching with ATLAS, D3FEND, NIST AI RMF, and CSF 2.0 fields.

All 754 skills now carry structured mappings for all 5 security frameworks:
- MITRE ATT&CK (in tags)
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- MITRE D3FEND v1.3 (d3fend_techniques)
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2026-04-06 11:17:40 +02:00

2.8 KiB

name, description, domain, subdomain, tags, version, author, license, nist_csf
name description domain subdomain tags version author license nist_csf
hunting-for-dns-based-persistence Hunt for DNS-based persistence mechanisms including DNS hijacking, dangling CNAME records, wildcard DNS abuse, and unauthorized zone modifications using passive DNS databases, SecurityTrails API, and DNS audit log analysis. cybersecurity threat-hunting
dns
persistence
threat-hunting
passive-dns
dns-hijacking
subdomain-takeover
securitytrails
1.0 mahipal Apache-2.0
DE.CM-01
DE.AE-02
DE.AE-07
ID.RA-05

Hunting for DNS-based Persistence

Overview

Attackers establish DNS-based persistence by hijacking DNS records, creating unauthorized subdomains, abusing wildcard DNS entries, or modifying NS delegations to redirect traffic through attacker-controlled infrastructure. These techniques survive credential rotations, endpoint reimaging, and traditional remediation because DNS changes persist independently of compromised hosts. Detection requires passive DNS historical analysis, zone file auditing, and monitoring for unauthorized record modifications. This skill covers hunting methodologies using SecurityTrails passive DNS API, DNS audit logs from Route53/Azure DNS/Cloudflare, and zone transfer analysis.

When to Use

  • When investigating security incidents that require hunting for dns based persistence
  • When building detection rules or threat hunting queries for this domain
  • When SOC analysts need structured procedures for this analysis type
  • When validating security monitoring coverage for related attack techniques

Prerequisites

  • SecurityTrails API key (free tier provides 50 queries/month)
  • Access to DNS provider audit logs (Route53, Azure DNS, Cloudflare, or on-premises DNS)
  • Python 3.9+ with requests library
  • DNS zone file access or AXFR capability for internal zones
  • Historical DNS baseline for comparison

Steps

Step 1: Baseline DNS Records

Export current DNS zone records and establish baseline for all authorized A, AAAA, CNAME, MX, NS, and TXT records.

Step 2: Query Passive DNS History

Use SecurityTrails API to retrieve historical DNS records and identify unauthorized changes, new subdomains, and CNAME records pointing to decommissioned services (dangling CNAMEs).

Step 3: Detect Anomalies

Compare current records against baseline to identify unauthorized modifications, wildcard records that resolve all subdomains, NS delegation changes, and MX record hijacking.

Step 4: Investigate Findings

Correlate DNS anomalies with threat intelligence feeds, check resolution targets against known malicious infrastructure, and validate record ownership.

Expected Output

JSON report listing DNS anomalies with record type, historical changes, risk severity, and remediation recommendations for each finding.