CVE-2018-3858 in Canvas Draw
Summary
by MITRE
An exploitable heap overflow exists in the TIFF parsing functionality of Canvas Draw version 4.0.0. A specially crafted TIFF image processed via the application can lead to an out-of-bounds write, overwriting arbitrary data. An attacker can deliver a TIFF image to trigger this vulnerability and gain the ability to execute code. A different vulnerability than CVE-2018-3857.
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Analysis
by VulDB Data Team • 04/18/2023
The vulnerability identified as CVE-2018-3858 represents a critical heap overflow condition within the TIFF parsing implementation of Canvas Draw version 4.0.0. This flaw resides in the application's handling of raster image files, specifically when processing TIFF format images through its core rendering engine. The vulnerability manifests as an out-of-bounds write operation that occurs during the parsing phase of malformed TIFF files, creating a pathway for arbitrary code execution. The flaw is particularly concerning because it allows remote attackers to craft malicious TIFF images that can be processed by the application, thereby enabling privilege escalation and system compromise.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the TIFF parser component. When Canvas Draw encounters a specially crafted TIFF image, the parser fails to properly bounds-check array accesses during the decompression and rendering processes. This deficiency creates a heap-based buffer overflow condition where attacker-controlled data can overwrite adjacent memory locations, potentially corrupting critical application structures or overwriting function pointers and return addresses. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the heap-based nature of the actual exploitation makes it more insidious and difficult to detect through standard memory protection mechanisms.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a complete remote code execution capability within the context of the running application. Successful exploitation allows adversaries to execute arbitrary code with the privileges of the Canvas Draw process, which typically runs with user-level permissions but may have elevated access depending on system configuration. The vulnerability's remote exploitability means that attackers can deliver malicious TIFF files through various attack vectors including email attachments, web downloads, or malicious websites, making it particularly dangerous in enterprise environments where users may encounter untrusted image files. The separate nature of this vulnerability from CVE-2018-3857 indicates that it affects different code paths within the application, suggesting a broader architectural issue in the image processing subsystem.
Mitigation strategies for CVE-2018-3858 should focus on immediate patch application from the vendor, as the most effective solution requires updating to a version that addresses the heap overflow condition through proper bounds checking and memory management. Organizations should implement network-level controls to block suspicious TIFF file transfers and deploy application whitelisting policies that restrict the execution of untrusted image processing applications. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution, as exploitation typically involves code injection through the overflow condition. Additionally, memory protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention should be enabled to reduce the effectiveness of potential exploitation attempts, though these protections may be insufficient against well-crafted attacks targeting heap-based vulnerabilities.