CVE-2017-2900 in 3d Creation Suite
Summary
by MITRE
An exploitable integer overflow exists in the PNG loading functionality of the Blender open-source 3d creation suite version 2.78c. A specially crafted '.png' file can cause an integer overflow resulting in a buffer overflow which can allow for code execution under the context of the application. An attacker can convince a user to use the file as an asset via the sequencer in order to trigger this vulnerability.
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Analysis
by VulDB Data Team • 03/07/2023
The vulnerability identified as CVE-2017-2900 represents a critical security flaw in Blender version 2.78c that manifests within the Portable Network Graphics file loading mechanism. This integer overflow vulnerability specifically targets the application's handling of PNG image files during the asset import process, particularly when these files are utilized within the sequencer component of the software. The flaw exists in the way Blender processes certain metadata or image dimensions within PNG files, creating a scenario where normal integer arithmetic operations can exceed their maximum representable values, leading to unexpected behavior in memory management.
The technical execution of this vulnerability involves a precise manipulation of PNG file structures that causes the application to perform integer arithmetic resulting in an overflow condition. When Blender attempts to parse specific PNG attributes, particularly those related to image dimensions or chunk sizes, the mathematical operations involved can produce values that exceed the bounds of the integer data types used for storage. This overflow subsequently propagates into a buffer overflow condition within the application's memory allocation routines, where the system attempts to allocate memory based on the corrupted integer values. The vulnerability is classified under CWE-190 as an integer overflow, which directly maps to the conditions that allow for memory corruption and potential code execution.
The operational impact of this vulnerability extends beyond simple application instability, presenting a significant threat to users who may unknowingly encounter malicious PNG files during their 3D creation workflows. Attackers can craft specially designed PNG files that, when imported as assets within Blender's sequencer, trigger the integer overflow condition and subsequently execute arbitrary code with the privileges of the running Blender process. This represents a privilege escalation scenario where user-level access to the application can potentially be leveraged for more severe system compromise. The vulnerability is particularly dangerous because it operates within the legitimate asset import functionality that users routinely employ, making it difficult to distinguish between benign and malicious files without proper validation mechanisms.
The exploitation pathway for this vulnerability requires social engineering elements where an attacker must convince a user to import or use a malicious PNG file within Blender's interface. The attack vector is particularly insidious because it targets the normal workflow of 3D artists who frequently work with various image assets and would not typically expect such files to be malicious. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would likely involve execution of malicious code through the application's normal processing pathways. Users working with Blender's sequencer functionality are at risk when handling external assets, particularly those received from untrusted sources or when collaborating on projects where asset integrity cannot be guaranteed.
Mitigation strategies for CVE-2017-2900 should focus on immediate software updates to versions that address the integer overflow conditions within the PNG loading code. Users should implement strict file validation procedures for all external assets and consider employing automated scanning tools that can detect potentially malicious PNG file structures before import. The fix typically involves implementing proper bounds checking and integer overflow detection mechanisms within the image loading routines, ensuring that all arithmetic operations are validated against maximum allowable values before memory allocation occurs. Additionally, users should consider isolating Blender execution in restricted environments or virtualized sandboxes to limit the potential impact of successful exploitation attempts, particularly in enterprise environments where multiple users may be working with shared assets and collaborative projects.