CVE-2016-3993 in imlib2
Summary
by MITRE
Off-by-one error in the __imlib_MergeUpdate function in lib/updates.c in imlib2 before 1.4.9 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via crafted coordinates.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/19/2022
The vulnerability identified as CVE-2016-3993 represents a critical off-by-one error within the imlib2 library's image processing functionality. This flaw exists in the __imlib_MergeUpdate function located in the lib/updates.c file of imlib2 versions prior to 1.4.9. The issue stems from improper boundary checking when handling image coordinates during merge operations, creating a condition where an attacker can manipulate input parameters to trigger memory access violations. The vulnerability specifically affects applications that utilize imlib2 for image processing tasks, making it particularly dangerous in environments where image handling is prevalent.
The technical implementation of this vulnerability exploits a fundamental buffer management flaw that occurs during coordinate validation within the merge update process. When crafted coordinates are processed through the __imlib_MergeUpdate function, the off-by-one error causes the system to read memory locations that are outside the intended buffer boundaries. This results in an out-of-bounds read condition that can be leveraged by remote attackers to crash the application or potentially execute arbitrary code depending on the system configuration. The flaw operates at the intersection of memory safety and input validation, making it a classic example of improper boundary checking that violates fundamental security principles.
The operational impact of CVE-2016-3993 extends beyond simple denial of service, as it can be exploited to cause application instability and system availability issues across numerous software platforms. Since imlib2 is widely used in desktop environments, web browsers, and image processing applications, this vulnerability affects a substantial portion of the software ecosystem. Attackers can remotely trigger the vulnerability by providing malicious image data with specially crafted coordinates that bypass normal input validation. The consequences include application crashes, system instability, and potential privilege escalation depending on the target application's execution context, making it a significant concern for system administrators and security professionals managing affected environments.
Mitigation strategies for this vulnerability require immediate patching of affected imlib2 installations to version 1.4.9 or later, which contains the necessary boundary checking fixes. System administrators should conduct comprehensive inventory assessments to identify all systems utilizing vulnerable imlib2 versions and prioritize remediation efforts accordingly. Additional protective measures include implementing strict input validation for image processing pipelines, deploying network segmentation to limit exposure, and establishing monitoring protocols to detect potential exploitation attempts. Organizations should also consider implementing application sandboxing techniques and privilege separation to limit the potential impact of successful exploitation attempts, aligning with defense-in-depth principles outlined in cybersecurity frameworks and standards such as those referenced in the CWE catalog under CWE-129 for improper boundary checking. The vulnerability's classification as a memory safety issue places it within the scope of ATT&CK technique T1499 for endpoint denial of service, emphasizing the need for comprehensive security controls across multiple defensive layers to prevent successful exploitation.