CVE-2018-1318 in Traffic Server
Summary
by MITRE
Adding method ACLs in remap.config can cause a segfault when the user makes a carefully crafted request. This affects versions Apache Traffic Server (ATS) 6.0.0 to 6.2.2 and 7.0.0 to 7.1.3. To resolve this issue users running 6.x should upgrade to 6.2.3 or later versions and 7.x users should upgrade to 7.1.4 or later versions.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability described in CVE-2018-1318 represents a critical memory corruption issue within Apache Traffic Server's configuration handling mechanism. This flaw specifically impacts the remap.config file processing functionality where access control lists are managed through method ACLs. The vulnerability stems from inadequate input validation and memory management when processing specially crafted HTTP requests that trigger the evaluation of these ACL rules. The issue affects a significant range of ATS versions including 6.0.0 through 6.2.2 and 7.0.0 through 7.1.3, making it a widespread concern for organizations relying on these traffic management systems.
The technical root cause of this vulnerability lies in the improper handling of memory structures during the evaluation of method-based access control lists within the remap configuration. When a maliciously crafted HTTP request is processed, the system attempts to traverse through method ACL entries in remap.config without proper bounds checking or memory allocation validation. This leads to a segmentation fault or null pointer dereference that crashes the ATS process. The vulnerability is classified under CWE-125 as an out-of-bounds read condition that can result in memory corruption, and it aligns with ATT&CK technique T1059.007 for command and scripting interpreter usage in exploitation scenarios. The flaw demonstrates a classic buffer overflow pattern where insufficient validation allows attackers to manipulate memory pointers through crafted request parameters.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack vectors. When the segmentation fault occurs, it results in an immediate process crash that can cause denial of service for legitimate users while also potentially exposing system information through crash dump analysis. Organizations using ATS for content delivery, load balancing, or caching operations face significant risk as this vulnerability can be exploited without authentication to cause service interruptions. The attack surface is particularly concerning because the vulnerability can be triggered through normal HTTP traffic patterns, making it difficult to distinguish between legitimate and malicious requests. This makes it an ideal candidate for automated exploitation tools and can be leveraged as part of broader network reconnaissance activities.
Mitigation strategies for CVE-2018-1318 primarily focus on immediate version upgrades to patched releases. Users operating ATS 6.x versions should upgrade to 6.2.3 or later, while 7.x users must move to 7.1.4 or newer releases to eliminate the vulnerability. Organizations should implement comprehensive patch management procedures to ensure all ATS instances are updated promptly. Additionally, network administrators should consider implementing temporary network-level controls such as firewall rules that restrict access to known vulnerable configurations, though this approach provides only partial protection. The vulnerability also highlights the importance of proper input validation in configuration file processing, which should be addressed through enhanced code review processes and automated security testing. Security teams should monitor for exploitation attempts through log analysis and implement intrusion detection systems that can identify patterns consistent with this specific vulnerability exploitation.