CVE-2018-20348 in libpff
Summary
by MITRE
libpff_item_tree_create_node in libpff_item_tree.c in libpff before experimental-20180714 allows attackers to cause a denial of service (infinite recursion) via a crafted file, related to libfdata_tree_get_node_value in libfdata_tree.c.
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Analysis
by VulDB Data Team • 06/20/2023
The vulnerability identified as CVE-2018-20348 represents a critical denial of service flaw within the libpff library, specifically affecting versions prior to experimental-20180714. This issue manifests through the libpff_item_tree_create_node function in libpff_item_tree.c, which fails to properly validate input data structures during node creation processes. The flaw creates a condition where maliciously crafted input files can trigger infinite recursive calls, leading to system resource exhaustion and application instability. The vulnerability is particularly concerning as it operates at the core parsing layer of the library, which is widely used for processing Outlook Personal Folders files across various platforms and applications.
The technical implementation of this vulnerability stems from inadequate boundary checking and recursion termination mechanisms within the tree data structure management code. When libfdata_tree_get_node_value in libfdata_tree.c processes malformed input data, it fails to properly validate the recursive traversal paths, allowing attackers to construct input files that create circular references or deeply nested structures. This results in the recursive function calls never reaching a base case termination condition, causing the application to consume excessive CPU cycles and memory resources. The CWE-674 classification applies here as this represents an uncontrolled recursion vulnerability that leads to excessive resource consumption and potential system instability. The vulnerability operates at the intersection of data parsing and memory management, making it particularly dangerous in environments where libpff is used for processing untrusted input.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can affect any application or system that relies on libpff for Outlook PST file processing. Attackers can exploit this flaw by crafting specially formatted PST files that, when processed by vulnerable applications, cause indefinite recursion and system resource depletion. This affects a wide range of software including email clients, forensic analysis tools, and document processing applications that depend on libpff functionality. The vulnerability is particularly dangerous in automated processing environments where batch operations might be triggered by malicious input files, potentially leading to widespread service disruption. Organizations using applications built on libpff are at risk of experiencing complete system unresponsiveness or crashes, with recovery requiring manual intervention and system restarts.
Mitigation strategies for CVE-2018-20348 primarily focus on immediate version updates and input validation enhancements. The most effective approach involves upgrading to libpff version experimental-20180714 or later, which contains the necessary patches to address the recursive traversal issue. Additionally, implementing robust input validation and size limiting mechanisms can provide defense-in-depth protection against malformed input files. System administrators should consider implementing file size limits and processing timeouts to prevent resource exhaustion attacks. Network-based mitigations include filtering suspicious file types and implementing sandboxing techniques for file processing. The ATT&CK framework classification for this vulnerability would fall under T1499.004 - Endpoint Denial of Service, as it targets system resources through malformed input processing. Organizations should also conduct thorough vulnerability assessments to identify all applications and systems that utilize libpff, ensuring comprehensive remediation across their entire infrastructure.