CVE-2017-10768 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 might allow attackers to cause a denial of service or possibly have unspecified other impact via a crafted .rle file, related to "Data from Faulting Address controls Branch Selection starting at ntdll_77df0000!RtlpInsertFreeBlock+0x00000000000001ca."
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Analysis
by VulDB Data Team • 10/22/2019
CVE-2017-10768 represents a critical vulnerability in XnView Classic for Windows version 2.40 that demonstrates a classic buffer overflow condition within the RLE (Run-Length Encoded) file parsing functionality. This vulnerability stems from inadequate input validation when processing maliciously crafted .rle files, allowing attackers to manipulate memory operations through faulting address manipulation that directly influences branch selection within the ntdll library. The specific faulting address ntdll_77df0000!RtlpInsertFreeBlock+0x00000000000001ca indicates that the vulnerability occurs during heap memory management operations where the program fails to properly validate the size or structure of incoming RLE data before attempting to process it. This flaw aligns with CWE-121, heap-based buffer overflow, and represents a direct exploitation of memory corruption vulnerabilities that have been documented extensively in cybersecurity literature. The vulnerability operates at the intersection of application-level parsing errors and operating system memory management functions, creating a pathway for attackers to potentially execute arbitrary code or cause system instability through carefully constructed input files.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable more sophisticated attack vectors that leverage the Windows kernel's memory management subsystem. When a malicious .rle file is processed, the application's failure to validate the data structure allows attackers to manipulate the execution flow by controlling branch selection logic within ntdll's heap management routines. This creates opportunities for privilege escalation attacks where attackers could potentially leverage the vulnerability to execute code with elevated privileges, particularly when the application runs with administrative rights or when the vulnerability is triggered through automated processing systems. The vulnerability's exploitation potential is further enhanced by its location within the core memory management functions of the Windows operating system, making it a prime target for attackers seeking to establish persistent access or escalate privileges within compromised systems. The faulting address specifically points to RtlpInsertFreeBlock, which is part of the Windows NT runtime library responsible for managing heap memory allocation and deallocation, indicating that the vulnerability directly impacts how the system handles memory operations.
Mitigation strategies for CVE-2017-10768 must address both the immediate application-level vulnerability and broader system security controls to prevent exploitation. Organizations should implement immediate patch management procedures to upgrade to XnView Classic versions that have addressed this vulnerability, as the original version 2.40 contains no built-in protections against malformed RLE file inputs. System administrators should deploy application whitelisting solutions to restrict execution of known vulnerable applications, particularly in environments where users might encounter untrusted file types. Network-level controls including email filtering and web application firewalls should be configured to block or scan for .rle file attachments that might contain malicious payloads. The vulnerability's classification under ATT&CK technique T1059.007 (Command and Scripting Interpreter: PowerShell) suggests that attackers might leverage this vulnerability to establish persistence through PowerShell scripts that could be executed after initial compromise. Security monitoring should focus on detecting anomalous memory access patterns or heap manipulation activities, as these would indicate potential exploitation attempts. Additionally, implementing proper input validation and sanitization controls at the application level, including bounds checking for all file format parsers, would prevent similar vulnerabilities from occurring in other software components. The vulnerability serves as a reminder of the importance of secure coding practices and the necessity of thorough input validation in multimedia processing applications that handle user-supplied file formats.