CVE-2010-4746 in 389 Directory Server
Summary
by MITRE
Multiple memory leaks in the normalization functionality in 389 Directory Server before 1.2.7.5 allow remote attackers to cause a denial of service (memory consumption) via "badly behaved applications," related to (1) Slapi_Attr mishandling in the DN normalization code and (2) pointer mishandling in the syntax normalization code, a different issue than CVE-2011-0019.
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Analysis
by VulDB Data Team • 10/17/2021
The CVE-2010-4746 vulnerability targets the 389 Directory Server, a robust open-source implementation of the Lightweight Directory Access Protocol that serves as a central repository for user and resource information in enterprise environments. This vulnerability specifically affects the directory server's normalization functionality, which is responsible for processing and standardizing directory entry data according to defined syntax rules. The flaw exists in versions prior to 1.2.7.5 and represents a significant security concern that can be exploited remotely by malicious actors to consume system resources and potentially disrupt service availability.
The technical implementation of this vulnerability stems from two distinct memory management flaws within the server's normalization code paths. The first issue involves Slapi_Attr mishandling within the DN (Distinguished Name) normalization code, where the server fails to properly manage memory allocations when processing directory names that do not conform to expected formats. This particular flaw manifests when applications submit malformed directory entries that trigger improper memory deallocation sequences. The second vulnerability occurs in the syntax normalization code where pointer management becomes corrupted during processing of malformed input data, leading to memory allocation that is never properly released back to the system.
The operational impact of CVE-2010-4746 creates a sustained denial of service condition that can progressively consume available memory resources on the affected server. Remote attackers can exploit this vulnerability by submitting specially crafted directory entries through badly behaved applications that leverage the normalization functionality. As the server processes these malformed entries, memory leaks accumulate over time, eventually leading to system instability, performance degradation, and complete service unavailability. This vulnerability is particularly concerning in enterprise environments where directory servers handle thousands of concurrent requests and maintain extensive directory databases.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-401, which describes improper handling of memory allocation and deallocation, and demonstrates characteristics consistent with the ATT&CK technique T1499.004 for network denial of service attacks. The vulnerability represents a classic case of resource exhaustion that can be exploited by attackers to compromise system availability without requiring authentication or privilege escalation. Organizations should implement immediate mitigation measures including applying the vendor-provided patch to version 1.2.7.5 or later, monitoring system memory consumption patterns for unusual spikes, and implementing network segmentation to limit exposure. Additionally, input validation should be strengthened at the application level to prevent malformed directory entries from reaching the normalization functionality, and regular security assessments should be conducted to identify similar memory management issues in other directory services and LDAP implementations.