CVE-2015-8779 in C Library
Summary
by MITRE
Stack-based buffer overflow in the catopen function in the GNU C Library (aka glibc or libc6) before 2.23 allows context-dependent attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a long catalog name.
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Analysis
by VulDB Data Team • 07/25/2022
The CVE-2015-8779 vulnerability represents a critical stack-based buffer overflow flaw within the GNU C Library implementation of the catopen function. This vulnerability affects glibc versions prior to 2.23 and demonstrates how seemingly benign library functions can become vectors for severe security compromises. The catopen function is part of the X/Open CAE Standard C Language Binding and is used to open catalog files for message localization, making it a common component in applications that require internationalization support. The flaw manifests when the function processes catalog names that exceed the allocated buffer space on the stack, creating conditions where attackers can manipulate memory layout and execution flow.
The technical exploitation of this vulnerability relies on the improper bounds checking within the catopen implementation where a fixed-size buffer is used to store catalog names without adequate validation of input length. This design flaw falls under the CWE-121 category of Stack-based Buffer Overflow, where insufficient bounds checking allows an attacker to write beyond the allocated buffer boundaries. The vulnerability is context-dependent meaning that exploitation requires specific conditions such as the application calling catopen with user-controllable input, and the attacker must have control over the catalog name parameter. The stack overflow occurs because the function does not validate that the incoming catalog name length fits within the predetermined buffer size, leading to potential overwrite of adjacent stack memory including return addresses and local variables.
From an operational impact perspective, this vulnerability can result in either denial of service through application crashes or more severe arbitrary code execution depending on exploitation circumstances and system protections. When the buffer overflow occurs, it typically leads to stack corruption that causes the application to terminate abnormally or behave unpredictably. However, under certain conditions with memory layout control and appropriate exploitation techniques, attackers may be able to overwrite the return address of the calling function, potentially redirecting execution flow to malicious code. The vulnerability affects a wide range of applications since glibc is fundamental to most unix-like systems and numerous software packages rely on it for standard library functionality. This makes the impact particularly severe as exploitation could potentially affect core system services, network applications, and user-level programs that utilize internationalization features.
The mitigation strategies for CVE-2015-8779 primarily focus on upgrading to glibc version 2.23 or later where the buffer overflow has been addressed through proper bounds checking and input validation. System administrators should prioritize patching affected systems as this vulnerability represents a significant risk to system integrity and availability. Additional mitigations include implementing address space layout randomization ASLR and stack canaries to make exploitation more difficult, though these are not complete solutions since the underlying buffer overflow remains. Organizations should also consider input validation at application level where possible and employ runtime protections such as stack protection mechanisms and heap integrity checks. The vulnerability aligns with ATT&CK technique T1068 for local privilege escalation and T1203 for exploitation of known vulnerabilities, making it a target for both casual attackers seeking system disruption and more sophisticated threat actors looking to establish persistent access through system compromise. Regular security assessments and vulnerability scanning should include detection of affected glibc versions to ensure comprehensive protection against this and similar stack-based buffer overflow vulnerabilities.