CVE-2018-15159 in libesedb
Summary
by MITRE
** DISPUTED ** The libesedb_page_read_tags function in libesedb_page.c in libesedb through 2018-04-01 allows remote attackers to cause a heap-based buffer over-read via a crafted esedb file. NOTE: the vendor has disputed this as described in the GitHub issue comments.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2018-15159 affects the libesedb library, a component used for reading Extensible Storage Engine database files commonly found in Windows systems. This library serves as a critical parsing mechanism for accessing .edb files that store various types of data including email messages, contacts, and other application-specific information. The issue resides within the libesedb_page_read_tags function located in the libesedb_page.c source file, which processes tag information within database pages. The vulnerability represents a heap-based buffer over-read that occurs when the library attempts to parse malformed or crafted esedb files, potentially leading to memory corruption and system instability. The affected version range extends through the 2018-04-01 release, indicating that this flaw existed for several months before it was identified and reported. This type of vulnerability falls under the category of memory safety issues that can be exploited to execute arbitrary code or cause denial of service conditions.
The technical exploitation of this vulnerability requires an attacker to craft a malicious esedb file that triggers the buffer over-read condition when processed by the vulnerable library. The heap-based nature of the over-read means that the attacker can potentially access memory locations beyond the intended buffer boundaries, which may contain sensitive data or executable code. The function in question likely performs operations that do not properly validate the size or structure of tag data within the database pages, allowing an attacker to manipulate the parsing logic into reading beyond allocated memory regions. This type of flaw typically arises from inadequate bounds checking or improper memory management during parsing operations, where the library fails to verify that the data being read matches expected formats and sizes. The vulnerability demonstrates a classic buffer over-read scenario that can be classified under CWE-125 as an out-of-bounds read, which is a common vector for information disclosure and potential code execution attacks.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable more sophisticated attacks depending on the execution environment. When a system processes the malicious esedb file, the heap corruption could lead to unpredictable behavior including application crashes, data corruption, or in some cases, the possibility of remote code execution. The library's widespread use in various applications and systems that handle email data makes this vulnerability particularly concerning for organizations relying on Exchange Server or other Microsoft products that utilize ESE databases. The vulnerability's remote exploitation capability means that attackers could potentially deliver malicious esedb files through various attack vectors including email attachments, web downloads, or file sharing platforms. From an attack chain perspective, this vulnerability could be leveraged as a stepping stone in broader exploitation campaigns, particularly when combined with other vulnerabilities or when the target environment has additional attack surface areas. The ATT&CK framework would categorize this as a software exploitation technique, potentially falling under the T1203 - Exploitation for Client Execution or T1059 - Command and Scripting Interpreter categories depending on the specific attack implementation.
Despite the vendor's disputed status regarding this CVE, the technical analysis reveals a legitimate concern that requires careful consideration. The disputed nature of the vulnerability suggests that either the exploitation conditions are not clearly reproducible, or the vendor believes the impact is overstated compared to other potential issues. However, the underlying memory safety issue remains valid and represents a fundamental flaw in the library's parsing logic. Organizations should continue to monitor updates and patches from the vendor while implementing defensive measures such as input validation, sandboxing of file processing, and network segmentation to limit potential impact. The vulnerability highlights the importance of proper memory management and bounds checking in database parsing libraries, particularly those handling untrusted data sources. Security practitioners should consider this issue as part of broader vulnerability management strategies, ensuring that all dependencies and libraries are kept current with security patches while maintaining awareness of vendor-stated positions on disputed vulnerabilities. The incident underscores the need for comprehensive testing of parsing functions against malformed inputs and the importance of maintaining robust security practices in database and file processing components.