CVE-2018-20217 : Vulnerability Insights and Analysis
Learn about CVE-2018-20217 affecting MIT Kerberos 5. Discover the impact, affected systems, exploitation details, and mitigation steps to secure your.#
MIT Kerberos 5 (krb5) prior to version 1.17 has a Reachable Assertion issue that can crash the Key Distribution Center (KDC) when a malicious actor obtains a krbtgt ticket using outdated encryption methods.
Understanding CVE-2018-20217
This CVE involves a vulnerability in MIT Kerberos 5 that allows attackers to crash the KDC by exploiting an S4U2Self request.
What is CVE-2018-20217?
The KDC in MIT Kerberos 5 before version 1.17 is susceptible to a Reachable Assertion issue. Attackers can cause the KDC to crash by acquiring a krbtgt ticket with outdated encryption methods and initiating an S4U2Self request.
The Impact of CVE-2018-20217
Exploiting this vulnerability can lead to a denial of service (DoS) condition by crashing the KDC, disrupting authentication processes within the Kerberos system.
Technical Details of CVE-2018-20217
MIT Kerberos 5 (krb5) version 1.17 and below are affected by this vulnerability.
Vulnerability Description
A Reachable Assertion issue in the KDC allows attackers to crash the system by acquiring a krbtgt ticket using older encryption types.
Affected Systems and Versions
- Product: MIT Kerberos 5
- Vendor: MIT
- Versions affected: <1.17
Exploitation Mechanism
- Attackers exploit outdated encryption methods (single-DES, triple-DES, or RC4) to acquire a krbtgt ticket.
- By initiating an S4U2Self request, the attacker prompts the KDC to crash.
Mitigation and Prevention
To address CVE-2018-20217, follow these mitigation strategies:
Immediate Steps to Take
- Update MIT Kerberos 5 to version 1.17 or above to mitigate the vulnerability.
- Monitor for any unauthorized access attempts or unusual KDC behavior.
Long-Term Security Practices
- Implement a regular security patch management process to stay protected against known vulnerabilities.
- Conduct regular security assessments and audits to identify and address any security gaps.
Patching and Updates
- Apply security updates and patches provided by MIT Kerberos promptly to address vulnerabilities and enhance system security.