The Challenge
A major security blind spot exists in modern Windows environments: Rivest Cipher 4 (RC4) encryption remains embedded in NTLMv2 authentication protocols across Active Directory infrastructures, including the latest Windows Server 2025 domain controllers. While maintained for compatibility and Kerberos fallback scenarios, RC4 presents significant security risks that conventional security tools often miss.
Why Traditional Tools Fall Short
Standard vulnerability scanners frequently overlook RC4 as a weakness because Microsoft hasn’t fully deprecated it from their Operating Systems (OSs). Since the OS and application versions themselves aren’t flagged as vulnerable, these scanners provide a false sense of security—even as the underlying cryptographic weaknesses remain exploitable.
The Risk
RC4’s vulnerabilities create multiple attack vectors:
- Keystream prediction attacks: Biases in RC4’s keystream enable attackers to predict encryption patterns after observing sufficient network traffic, like the 2013 BEAST attack on TLS
- Offline password cracking: Captured NTLMv2 challenge-response pairs become targets for brute-force attacks
- Pass-the-Hash attacks: NTLM hashes functioning as RC4 keys can be reused to gain unauthorized access without ever cracking the actual password
- Amplified risks in hybrid environments: RC4 usage compounds security concerns in environments mixing Kerberos and NTLM authentication
The Tychon Solution
Unlike conventional vulnerability scanners that rely solely on version checking, Tychon employs deep cryptographic inspection capabilities. Our platform discovers RC4 implementations through comprehensive local file and binary analysis identifying the protocol even when dormant or unused.
Organizations using Tychon gain visibility into vulnerabilities that would otherwise remain hidden, enabling them to:
- Identify and remediate weak encryption protocols before they’re exploited
- Make informed decisions about authentication protocol configurations
- Enhance overall security posture and resilience against sophisticated attacks
- Move proactively toward cryptographic modernization
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