CVE-2014-3042 in CICS Transaction Server
Summary
by MITRE
IBM CICS Transaction Server 3.1, 3.2, 4.1, 4.2, and 5.1 on z/OS does not properly implement CEMT transactions, which allows remote authenticated users to cause a denial of service (storage overlay) by using a 3270 emulator to send an invalid 3270 data stream.
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Analysis
by VulDB Data Team • 03/12/2018
The vulnerability identified as CVE-2014-3042 affects IBM CICS Transaction Server versions 3.1 through 5.1 running on z/OS operating systems. This issue represents a critical security flaw in the CICS Enterprise Management Transaction (CEMT) implementation that can be exploited by authenticated remote attackers to cause system-level disruptions. The vulnerability specifically targets the handling of 3270 data streams within the CICS environment, which are commonly used for terminal emulation and communication with mainframe systems. The affected versions of CICS Transaction Server process these data streams through the CEMT transaction mechanism, which is designed to manage and control CICS resources and transactions.
The technical flaw stems from inadequate validation and processing of 3270 data streams within the CEMT transaction framework. When a remote authenticated user sends an invalid 3270 data stream through a 3270 emulator, the system fails to properly validate the incoming data before processing it within the CEMT transaction context. This improper validation leads to a storage overlay condition where the system's memory management becomes corrupted. The vulnerability manifests as a denial of service condition that can potentially cause the CICS region to crash or become unresponsive, effectively preventing legitimate transactions from being processed.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the integrity of the entire CICS transaction processing environment. A successful exploitation can result in complete system unavailability for the duration of the denial of service, affecting all applications and services that depend on the affected CICS region. The vulnerability affects organizations running critical business applications on mainframe systems, where CICS Transaction Server serves as the primary transaction processing engine. The remote nature of the attack means that unauthorized users can exploit this flaw from external network locations, making it particularly dangerous for organizations with exposed mainframe systems. The storage overlay condition can potentially lead to data corruption or loss, depending on the timing and nature of the attack.
Organizations should implement immediate mitigations including applying the relevant IBM security patches and fixes released for this vulnerability. Network segmentation and access controls should be strengthened to limit access to CICS systems and reduce the attack surface. Monitoring and logging should be enhanced to detect anomalous 3270 data stream activity that might indicate exploitation attempts. The vulnerability aligns with CWE-129, which covers improper validation of input ranges, and represents a classic example of how insufficient input validation can lead to memory corruption vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 for network denial of service and T1566.001 for malicious file execution through terminal emulation. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious 3270 data stream patterns, as well as establishing incident response procedures specifically tailored to handle mainframe security incidents. Regular vulnerability assessments and security audits of CICS environments are essential to identify and remediate similar issues before they can be exploited by malicious actors.