CVE-1999-0199 in C Library
Summary
by MITRE • 10/06/2020
manual/search.texi in the GNU C Library (aka glibc) before 2.2 lacks a statement about the unspecified tdelete return value upon deletion of a tree's root, which might allow attackers to access a dangling pointer in an application whose developer was unaware of a documentation update from 1999.
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Analysis
by VulDB Data Team • 11/16/2020
The vulnerability described in CVE-1999-0199 pertains to a documentation gap within the GNU C Library's manual documentation file manual/search.texi. This issue affects glibc versions prior to 2.2 and specifically concerns the tdelete function behavior within the tree deletion mechanism. The problem manifests when applications utilize the tdelete function to remove nodes from a binary search tree structure, particularly when deleting the root node of the tree. The documentation fails to specify that the tdelete function returns a dangling pointer when the root node is deleted, creating a potential security risk for applications that may not be properly handling this return value.
The technical flaw stems from insufficient documentation regarding the behavior of the tdelete function in the context of tree manipulation within the glibc library. When an application calls tdelete to remove the root node of a tree, the function returns a pointer to memory that may no longer be valid or accessible. This occurs because the function does not properly handle the memory management aspect of root node deletion, leaving applications that rely on the return value to potentially access freed memory locations. The vulnerability represents a classic case of improper memory handling that can lead to undefined behavior and potential exploitation by malicious actors who understand how to leverage such documentation gaps.
The operational impact of this vulnerability extends beyond simple documentation issues, as it creates opportunities for memory corruption and potential code execution in applications that improperly handle the return value of tdelete. Applications that do not explicitly check for or properly manage the dangling pointer returned by tdelete after root deletion may experience crashes, data corruption, or more severe security implications. This vulnerability particularly affects systems that heavily rely on tree-based data structures and the standard library functions for memory management. The issue demonstrates how inadequate documentation can create security risks, as developers may make assumptions about function behavior based on incomplete information.
From a cybersecurity perspective, this vulnerability aligns with CWE-754, which addresses "Improper Check for Unusual or Exceptional Conditions," and represents a form of documentation-based security flaw that can be exploited through improper handling of return values. The vulnerability also relates to ATT&CK technique T1059.007, which involves the use of system services and libraries for execution, as applications may be manipulated to exploit improper memory handling. The risk is elevated in environments where applications are not thoroughly tested for memory management issues, particularly in systems that depend on the GNU C Library for core system functionality. The vulnerability underscores the importance of comprehensive documentation and proper memory management practices in security-critical system components. Organizations should ensure that all system libraries are properly updated to address such documentation gaps and that application developers are trained to handle return values from system functions appropriately to prevent exploitation of similar issues.