CVE-2018-19565 in dcraw
Summary
by MITRE
A buffer over-read in crop_masked_pixels in dcraw through 9.28 could be used by attackers able to supply malicious files to crash an application that bundles the dcraw code or leak private information.
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Analysis
by VulDB Data Team • 04/15/2020
The vulnerability identified as CVE-2018-19565 represents a critical buffer over-read flaw within the dcraw library version 9.28 and earlier, affecting applications that incorporate this code for raw image processing. This issue specifically occurs within the crop_masked_pixels function, which is responsible for handling pixel data manipulation during image cropping operations. The flaw stems from insufficient bounds checking when processing malformed image files, creating a scenario where an attacker can craft malicious input that triggers memory access beyond allocated buffer boundaries. Such buffer over-read conditions typically arise when software reads data beyond the intended memory limits, potentially exposing sensitive information stored in adjacent memory locations or causing application instability through crashes.
The technical exploitation of this vulnerability demonstrates a classic security flaw categorized under CWE-125, which defines "Out-of-bounds Read" as a condition where a program reads data past the end of a valid buffer. When dcraw processes maliciously crafted image files, the crop_masked_pixels function fails to properly validate input parameters, leading to unauthorized memory access patterns. This type of vulnerability can be particularly dangerous in applications that handle untrusted image data from external sources, as attackers can leverage the flaw to either cause denial of service through application crashes or potentially extract sensitive information from memory segments adjacent to the vulnerable buffer. The attack surface expands significantly when considering that dcraw is widely integrated into various image processing applications, digital asset management systems, and photography software packages.
The operational impact of CVE-2018-19565 extends beyond simple application instability, presenting both availability and confidentiality risks to affected systems. When exploited, the buffer over-read can cause applications to crash unpredictably, leading to denial of service conditions that disrupt legitimate user operations and potentially allowing attackers to perform repeated crash attacks against vulnerable services. Additionally, the memory leakage aspect of this vulnerability creates information disclosure risks where private data stored in memory adjacent to the vulnerable buffer might be exposed to unauthorized parties. This type of vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as attackers may leverage such flaws to establish persistent access through compromised applications or to gather intelligence from system memory. The vulnerability affects a broad range of applications including photo editing software, digital asset management platforms, and any system that processes raw image formats using the dcraw library.
Mitigation strategies for CVE-2018-19565 require immediate action to upgrade to dcraw version 9.29 or later, where the buffer over-read has been addressed through proper bounds checking implementation. System administrators should conduct comprehensive vulnerability assessments to identify all applications that utilize the affected dcraw library and ensure timely patch deployment across all affected systems. Network security controls should include monitoring for suspicious image file uploads that might be used to exploit this vulnerability, particularly in web applications that accept user-generated content. Additionally, implementing proper input validation and sanitization measures can help reduce the attack surface by preventing malformed image data from reaching the vulnerable code paths. The fix for this vulnerability typically involves adding proper boundary checks before buffer access operations, ensuring that all input parameters are validated against expected ranges and that memory access operations remain within allocated buffer limits. Organizations should also consider implementing application sandboxing or containerization strategies to limit the potential impact of successful exploitation attempts, thereby reducing the risk of information disclosure or system compromise.