CVE-2017-6153 in BIG-IP
Summary
by MITRE
Features in F5 BIG-IP 13.0.0-13.1.0.3, 12.1.0-12.1.3.1, 11.6.1-11.6.3.1, 11.5.1-11.5.5, or 11.2.1 system that utilizes inflate functionality directly, via an iRule, or via the inflate code from PEM module are subjected to a service disruption via a "Zip Bomb" attack.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 03/19/2023
The vulnerability identified as CVE-2017-6153 affects F5 BIG-IP systems across multiple versions including 13.0.0-13.1.0.3, 12.1.0-12.1.3.1, 11.6.1-11.6.3.1, 11.5.1-11.5.5, and 11.2.1, presenting a critical security risk through Zip Bomb attack vectors. This flaw specifically targets systems that utilize inflate functionality either directly through iRules or via the inflate code from the PEM module, creating a significant service disruption potential. The vulnerability operates by exploiting the decompression process within these systems, allowing malicious actors to craft specially designed compressed files that appear small but expand to enormous sizes during decompression.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within the inflate functionality of the BIG-IP system. When processing compressed data, the system fails to properly monitor or limit the expansion ratio of compressed content, enabling attackers to submit maliciously crafted zip files that trigger excessive memory consumption and CPU utilization. This represents a classic example of a resource exhaustion attack that can lead to complete service disruption. The vulnerability is categorized under CWE-400 as "Uncontrolled Resource Consumption" and aligns with ATT&CK technique T1499.004 for "File System Wipe" and T1070.004 for "File Deletion" when considering the broader impact on system availability.
The operational impact of CVE-2017-6153 extends beyond simple denial of service, as it can effectively render BIG-IP systems unusable for legitimate traffic while consuming all available system resources. Attackers can exploit this vulnerability through iRules that process user-supplied data or through the PEM module which handles various types of compressed content. The attack vector typically involves submitting a compressed file with an extremely high compression ratio, where a few kilobytes of compressed data expands to gigabytes or even terabytes of decompressed content. This can cause memory allocation failures, process termination, and ultimately complete system unavailability. The vulnerability is particularly dangerous in network infrastructure devices like load balancers and application delivery controllers where continuous availability is critical.
Mitigation strategies for CVE-2017-6153 should include immediate deployment of F5's official security patches and updates, which address the underlying inflate functionality issues. Organizations should implement strict input validation policies for all compressed content processed through iRules and the PEM module, establishing limits on compression ratios and maximum decompressed file sizes. Network segmentation and traffic filtering can help reduce exposure by limiting access to vulnerable iRule endpoints. System administrators should also configure monitoring and alerting for unusual resource consumption patterns that might indicate exploitation attempts. The implementation of rate limiting and connection throttling mechanisms can provide additional protection layers. Additionally, regular security assessments and vulnerability scanning should be conducted to identify any potential exploitation attempts, with network traffic analysis being crucial for detecting anomalous behavior patterns associated with Zip Bomb attacks. Organizations should also consider implementing web application firewalls and intrusion detection systems that can identify and block malicious compressed content before it reaches the vulnerable system components.