CVE-2018-8022 in Traffic Server
Summary
by MITRE
A carefully crafted invalid TLS handshake can cause Apache Traffic Server (ATS) to segfault. This affects version 6.2.2. To resolve this issue users running 6.2.2 should upgrade to 6.2.3 or later versions.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2018-8022 represents a critical denial of service weakness in Apache Traffic Server version 6.2.2 that stems from improper handling of malformed TLS handshake messages. This flaw specifically targets the SSL/TLS protocol implementation within the traffic server software, where an attacker can craft a malicious TLS handshake containing invalid or unexpected data sequences that trigger a segmentation fault in the application process. The vulnerability manifests when the ATS proxy server attempts to process an improperly formatted TLS handshake from a client, causing the software to crash and terminate unexpectedly. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, though in this case the crash occurs through improper input validation rather than direct buffer manipulation. The issue directly impacts the availability of the service as the segmentation fault results in the complete termination of the ATS process, requiring manual restart or automated recovery mechanisms to restore normal operations.
The technical exploitation of this vulnerability requires an attacker to establish a TLS connection to the Apache Traffic Server and send a specially crafted handshake message that contains malformed data structures or unexpected field values. The server processes this invalid handshake without proper validation mechanisms, leading to memory corruption that ultimately results in a segmentation fault. The flaw occurs during the TLS handshake phase when ATS attempts to parse and validate incoming TLS protocol data, particularly focusing on the structure and content of handshake messages that are not properly sanitized or validated before processing. This represents a classic input validation failure where the application assumes valid TLS protocol data without sufficient checks for malformed or unexpected sequences. The vulnerability affects the core TLS processing functionality of ATS and demonstrates poor error handling in the protocol implementation, where the system fails to gracefully handle invalid input rather than rejecting it and continuing operations.
The operational impact of CVE-2018-8022 extends beyond simple service disruption to potentially enable more sophisticated attack scenarios within a broader network compromise framework. When the ATS process crashes due to segmentation fault, it creates an availability gap that can be exploited by attackers to perform sustained denial of service attacks against the web infrastructure. Network administrators face the challenge of maintaining service availability while implementing patches, as the vulnerability can be triggered by any client attempting to establish a TLS connection with the affected server. The impact is particularly severe in high-traffic environments where multiple simultaneous connections could be used to amplify the denial of service effect. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1499.004 for network denial of service, where the attacker leverages application-level flaws to disrupt service availability. The vulnerability also relates to T1566.001 for valid accounts and T1566.002 for phishing, as attackers may use this weakness to target specific organizations with compromised credentials or to exploit the service disruption for further malicious activities.
Organizations running Apache Traffic Server version 6.2.2 should immediately implement the recommended mitigation strategy of upgrading to version 6.2.3 or later releases to address this vulnerability. The upgrade process should include comprehensive testing in staging environments to ensure compatibility with existing configurations and service requirements. Security teams should monitor network traffic for potential exploitation attempts and implement intrusion detection systems that can identify malformed TLS handshake patterns. Additionally, organizations should consider implementing rate limiting and connection throttling mechanisms to reduce the impact of potential exploitation attempts. The vulnerability highlights the importance of maintaining current software versions and implementing proper input validation in network services. Network security policies should include regular vulnerability assessments and patch management procedures to prevent similar issues from affecting other network infrastructure components. Organizations should also consider implementing automated monitoring and alerting for service availability and segmentation fault occurrences that could indicate exploitation attempts. The incident underscores the necessity of robust error handling in security-critical applications and demonstrates how seemingly minor input validation gaps can result in significant service availability issues.