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mukul975
52 lines
1.5 KiB
Markdown
52 lines
1.5 KiB
Markdown
---
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name: analyzing-tls-certificate-transparency-logs
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description: >
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Queries Certificate Transparency logs via crt.sh and pycrtsh to detect phishing
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domains, unauthorized certificate issuance, and shadow IT. Monitors newly issued
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certificates for typosquatting and brand impersonation using Levenshtein distance.
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Use for proactive phishing domain detection and certificate monitoring.
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domain: cybersecurity
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subdomain: security-operations
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tags: [analyzing, tls, certificate, transparency]
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version: "1.0"
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author: mahipal
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license: MIT
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---
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# Analyzing TLS Certificate Transparency Logs
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## Instructions
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Query crt.sh Certificate Transparency database to find certificates issued for
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domains similar to your organization's brand, detecting phishing infrastructure.
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```python
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from pycrtsh import Crtsh
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c = Crtsh()
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# Search for certificates matching a domain
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certs = c.search("example.com")
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for cert in certs:
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print(cert["id"], cert["name_value"])
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# Get full certificate details
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details = c.get(certs[0]["id"], type="id")
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```
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Key analysis steps:
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1. Query crt.sh for all certificates matching your domain pattern
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2. Identify certificates with typosquatting variations (Levenshtein distance)
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3. Flag certificates from unexpected CAs
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4. Monitor for wildcard certificates on suspicious subdomains
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5. Cross-reference with known phishing infrastructure
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## Examples
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```python
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from pycrtsh import Crtsh
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c = Crtsh()
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certs = c.search("%.example.com")
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for cert in certs:
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print(f"Issuer: {cert.get('issuer_name')}, Domain: {cert.get('name_value')}")
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```
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