CVE-2015-5229 in Red Hat
Summary
by MITRE
The calloc function in the glibc package in Red Hat Enterprise Linux (RHEL) 6.7 and 7.2 does not properly initialize memory areas, which might allow context-dependent attackers to cause a denial of service (hang or crash) via unspecified vectors.
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Analysis
by VulDB Data Team • 07/12/2022
The vulnerability identified as CVE-2015-5229 represents a critical memory initialization flaw within the glibc implementation of the calloc function on Red Hat Enterprise Linux systems. This issue affects versions 6.7 and 7.2 of the enterprise operating system, where the calloc function fails to properly initialize allocated memory regions before returning them to applications. The flaw stems from improper handling of memory allocation operations that should guarantee zero-initialization of newly allocated memory blocks, a fundamental security and stability requirement for heap management functions. According to CWE-754, this vulnerability manifests as a weakness in resource management that can lead to unpredictable application behavior and system instability.
The technical nature of this vulnerability lies in the violation of standard memory allocation protocols where calloc is expected to provide both memory allocation and initialization services. When applications call calloc, they anticipate receiving memory blocks that are pre-initialized to zero, which is essential for preventing information leakage and ensuring predictable program behavior. The failure in glibc's implementation means that memory areas may contain residual data from previous allocations, creating potential vectors for information disclosure and system instability. This flaw operates at the kernel level memory management interface and affects all applications relying on standard heap allocation mechanisms.
The operational impact of CVE-2015-5229 extends beyond simple memory corruption, as it can be exploited by context-dependent attackers to trigger denial of service conditions that may result in system hangs or application crashes. Attackers can leverage this vulnerability through unspecified vectors that likely involve crafting specific memory allocation patterns or exploiting applications that heavily rely on calloc functionality. The vulnerability's exploitation potential aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a significant threat to system availability and stability. Systems running affected RHEL versions become susceptible to cascading failures when applications encounter uninitialized memory regions during operation.
Mitigation strategies for CVE-2015-5229 focus on immediate system updates and patches provided by Red Hat to address the glibc implementation flaw. Organizations should prioritize applying the official security patches released for RHEL 6.7 and 7.2, as these updates specifically target the calloc function's improper memory initialization behavior. Additionally, system administrators should implement monitoring solutions to detect anomalous memory allocation patterns and consider runtime protections such as address space layout randomization and stack canaries to reduce exploitation success rates. The vulnerability demonstrates the critical importance of maintaining up-to-date system libraries and underscores the necessity of comprehensive security testing for core system components that handle memory management operations.