CVE-2011-1417 in iOS
Summary
by MITRE
Integer overflow in QuickLook, as used in Apple Mac OS X before 10.6.7 and MobileSafari in Apple iOS before 4.2.7 and 4.3.x before 4.3.2, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a Microsoft Office document with a crafted size field in the OfficeArtMetafileHeader, related to OfficeArtBlip, as demonstrated on the iPhone by Charlie Miller and Dion Blazakis during a Pwn2Own competition at CanSecWest 2011.
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Analysis
by VulDB Data Team • 10/19/2021
The vulnerability described in CVE-2011-1417 represents a critical integer overflow flaw within Apple's QuickLook framework that affected multiple operating systems including Mac OS X versions prior to 10.6.7 and iOS versions before 4.2.7 and 4.3.2. This issue specifically manifests when processing Microsoft Office documents through the QuickLook preview functionality, creating a dangerous condition that can be exploited by remote attackers to gain unauthorized code execution privileges or cause system instability through memory corruption and application crashes.
The technical flaw occurs within the OfficeArtMetafileHeader structure processing within the QuickLook component, where a crafted size field in the OfficeArtBlip data structure triggers an integer overflow condition. This overflow results in improper memory allocation calculations that can lead to buffer overflows and subsequent memory corruption. The vulnerability leverages the OfficeArtBlip format which is used to store bitmap images within Microsoft Office documents, making it particularly dangerous as it can be triggered simply by opening or previewing a maliciously crafted document. The integer overflow specifically affects the calculation of memory allocation sizes, causing the application to allocate insufficient memory for processing the crafted data structure, which then leads to memory corruption when the application attempts to write beyond allocated boundaries.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to include full remote code execution capabilities that could be exploited by attackers to compromise user systems. During the Pwn2Own competition at CanSecWest 2011, researchers Charlie Miller and Dion Blazakis demonstrated that this vulnerability could be reliably exploited on iPhone devices, showing how a remote attacker could craft a Microsoft Office document that would trigger the integer overflow when processed by MobileSafari's QuickLook functionality. The exploitation chain involves the attacker sending a specially crafted Office document to a victim, who then opens it in MobileSafari or Mac OS X QuickLook, leading to arbitrary code execution or system crashes. This vulnerability directly maps to CWE-190, which describes integer overflow conditions, and represents a classic example of how buffer overflow vulnerabilities can be leveraged for privilege escalation and system compromise.
The attack vectors for this vulnerability are particularly concerning as they leverage common document formats that users frequently encounter in email attachments and file sharing scenarios. The fact that this vulnerability affects both desktop and mobile platforms demonstrates the widespread nature of the flaw and the importance of comprehensive patch management across all affected systems. The vulnerability's exploitation requires minimal user interaction beyond opening the malicious document, making it particularly dangerous in phishing attacks and targeted campaigns. Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.007, which covers command and scripting interpreter usage, as the successful exploitation would likely involve executing malicious code through the compromised QuickLook process.
Mitigation strategies for CVE-2011-1417 require immediate patch deployment across all affected Apple operating systems, including Mac OS X 10.6.7 and later versions, as well as iOS 4.2.7 and 4.3.2 updates. Organizations should implement network-based controls to block or scan Microsoft Office document attachments from untrusted sources, particularly in environments where users may be exposed to potentially malicious content. Additionally, system administrators should consider disabling QuickLook previews for untrusted documents or implementing sandboxing measures to limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of regular security updates and demonstrates how seemingly minor flaws in document processing libraries can have significant security implications when combined with user interaction requirements.