CVE-2011-0241 in Safari
Summary
by MITRE
Heap-based buffer overflow in ImageIO in Apple Safari before 5.0.6 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted TIFF image with CCITT Group 4 encoding.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 11/15/2021
The vulnerability identified as CVE-2011-0241 represents a critical heap-based buffer overflow within Apple Safari's ImageIO framework, specifically affecting versions prior to 5.0.6. This flaw resides in the handling of TIFF image files that utilize CCITT Group 4 encoding, a compression standard commonly used in fax and document imaging applications. The vulnerability demonstrates the classic characteristics of heap corruption issues where insufficient bounds checking allows attackers to write beyond allocated memory boundaries, potentially leading to arbitrary code execution or system instability.
The technical implementation of this vulnerability stems from improper validation of image data structures within the ImageIO framework. When Safari processes a specially crafted TIFF image containing CCITT Group 4 encoded data, the parsing routine fails to adequately verify the size and structure of the compressed data segments. This oversight creates a condition where attacker-controlled data can overwrite adjacent heap memory regions, potentially corrupting critical program state or redirecting execution flow. The heap-based nature of the overflow indicates that the vulnerability occurs in dynamically allocated memory areas, making exploitation more complex but still highly dangerous as it can lead to complete system compromise.
The operational impact of this vulnerability extends beyond simple application crashes to encompass full system compromise capabilities. Remote attackers can leverage this flaw to execute arbitrary code with the privileges of the Safari process, which typically runs with user-level permissions but can potentially escalate to higher privileges depending on system configuration. The vulnerability's remote exploitability means that attackers can deliver malicious TIFF images through web browsers without requiring user interaction beyond visiting a compromised website. This characteristic aligns with ATT&CK technique T1203 for Exploitation for Client Execution and CWE-121 for Stack-based Buffer Overflow, though the heap-based nature places it more specifically within CWE-122 categories related to heap-based buffer overflows.
Systems running affected versions of Safari are particularly vulnerable due to the widespread use of TIFF images in web environments, especially in document sharing and publishing scenarios. The CCITT Group 4 encoding specifically creates conditions where the decompression process can be manipulated to trigger the buffer overflow, making this vulnerability particularly insidious as it can be triggered by legitimate image processing operations. Organizations should prioritize immediate patching of affected systems and implement network-level controls to block suspicious image file types. The vulnerability's classification under the broader category of memory corruption issues highlights the critical need for robust input validation and memory safety mechanisms in multimedia processing libraries. Security professionals should also monitor for related exploitation attempts targeting similar image processing vulnerabilities in other applications and browsers, as this flaw represents a well-established attack vector that has been extensively documented in exploit databases and security research publications.