CVE-2018-5532 : Vulnerability Insights and Analysis

In F5 BIG-IP versions 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, or 11.2.1-11.5.6, a vulnerability exists where a domain name stored in the TMM's DNS Cache may still be resolved even after the record is revoked by the parent server, potentially leading to information leakage.

Understanding CVE-2018-5532

This CVE involves a flaw in F5 BIG-IP that could allow a cached domain name to remain resolvable by the DNS Cache even after revocation by the parent server.

What is CVE-2018-5532?

The vulnerability in F5 BIG-IP versions 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, or 11.2.1-11.5.6 allows a domain name to be resolved by the cache even after revocation by the parent server, especially under continuous requests for the cached name.

The Impact of CVE-2018-5532

The vulnerability could result in information leakage due to the continued resolution of domain names by the DNS Cache, even after revocation by the parent server.

Technical Details of CVE-2018-5532

This section provides more technical insights into the vulnerability.

Vulnerability Description

The flaw allows a domain name stored in the TMM's DNS Cache to remain resolvable even after revocation by the parent server, potentially leading to information leakage.

Affected Systems and Versions

Product: BIG-IP (LTM, AAM, AFM, Analytics, APM, ASM, DNS, Edge Gateway, FPS, GTM, Link Controller, PEM, WebAccelerator)
Vendor: F5 Networks, Inc.
Versions: 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, 11.2.1-11.5.6

Exploitation Mechanism

The vulnerability occurs when the DNS Cache of TMM continues to resolve a domain name even after the parent server revokes the record, especially when there is a continuous stream of requests for the cached name.

Mitigation and Prevention

To address CVE-2018-5532, follow these mitigation strategies:

Immediate Steps to Take

Monitor DNS resolution activities for any unusual behavior.
Implement network traffic monitoring to detect potential information leakage.
Apply patches or updates provided by F5 Networks.

Long-Term Security Practices

Regularly update and patch F5 BIG-IP systems to mitigate known vulnerabilities.
Conduct security audits to identify and address any potential weaknesses in DNS caching mechanisms.

Patching and Updates

Apply the necessary patches or updates released by F5 Networks to address the vulnerability and enhance system security.