🛡️ Sentinel: [CRITICAL] Fix SSRF bypass via IPv4-mapped IPv6 addresses

[ManupaKDU]

🚨 Severity: CRITICAL
💡 Vulnerability: Attackers could bypass SSRF IP blocklists (e.g., checking is_link_local to block AWS metadata endpoints like 169.254.169.254) by passing the equivalent IPv4-mapped IPv6 address (e.g., ::ffff:169.254.169.254). Python's ipaddress module evaluates is_link_local and is_unspecified as False for these mapped addresses, allowing them past validation logic. The underlying OS networking stack then natively routes the IPv6 mapped packet to the IPv4 target, resulting in SSRF.
🎯 Impact: An attacker could use this network scanning utility to probe internal cloud infrastructure metadata endpoints or loopback services, gaining unauthorized access or mapping internal architecture.
🔧 Fix: Explicitly unwrapped the mapped IPv4 address using getattr(ip_obj, 'ipv4_mapped', None) and applied the security validation blocklist directly to the underlying IPv4Address object if it exists.
✅ Verification: Added a comprehensive unit test suite in test_testping1.py validating that IPv4-mapped loops, link-locals, multicasters, unspecifieds, and reserved addresses are strictly rejected. Tests pass with python3 -m unittest test_testping1.py.

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PR created automatically by Jules for task 1602020334448431204 started by @ManupaKDU

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