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hunting-for-dns-based-persistence

hunting-for-dns-based-persistence

github.com/mukul975Security35.2k61 installsUpdated 8w ago
Repository

About hunting-for-dns-based-persistence

A security skill for hunting DNS-based persistence through record changes, unauthorized subdomains, wildcard entries, and altered delegations. It uses passive DNS history, provider audit logs, and zone analysis to identify anomalies and produce a JSON findings report.

Key features

  1. 01Establish DNS record baselines
  2. 02Query passive DNS history
  3. 03Detect record and delegation anomalies
  4. 04Correlate findings with threat intelligence
  5. 05Report severity and remediation

Use cases

  1. 01Investigate DNS persistence after an incident
  2. 02Identify dangling CNAMEs and unauthorized subdomains
  3. 03Validate monitoring for DNS record changes

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/mukul975/anthropic-cybersecurity-skills --skill hunting-for-dns-based-persistence

After installing, type/hunting-for-dns-based-persistencein Claude Code to confirm it loaded.

Bundled files

References and scripts installed along with SKILL.md.

LICENSE
references/
api-reference.md
scripts/
agent.py

Details

From the project README

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.

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