CVE-2011-0206 in Mac OS X
Summary
by MITRE
Buffer overflow in International Components for Unicode (ICU) in Apple Mac OS X before 10.6.8 allows context-dependent attackers to execute arbitrary code or cause a denial of service (application crash) via vectors involving uppercase strings.
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Analysis
by VulDB Data Team • 11/13/2021
The vulnerability identified as CVE-2011-0206 represents a critical buffer overflow flaw within the International Components for Unicode (ICU) library implementation in Apple Mac OS X operating systems. This security weakness affects versions prior to 10.6.8 and stems from improper handling of string manipulation operations, specifically when processing uppercase string conversions. The ICU library serves as a fundamental component for internationalization and Unicode support across numerous Apple applications and system services, making this vulnerability particularly dangerous as it can potentially impact a wide range of software within the ecosystem.
The technical flaw manifests when the system processes certain uppercase string transformations, where the input validation fails to properly check the boundaries of memory allocations. This buffer overflow occurs during the conversion of lowercase characters to uppercase, particularly when dealing with malformed or specially crafted input strings that exceed the allocated buffer space. The vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The attack vector is context-dependent, meaning that successful exploitation requires specific conditions and knowledge of how to craft the malicious input to trigger the overflow during string processing operations.
The operational impact of this vulnerability extends beyond simple application crashes, as it provides attackers with the potential to execute arbitrary code with the privileges of the affected application. When the buffer overflow occurs, it can corrupt the stack frame and potentially overwrite return addresses, allowing for code injection attacks. This capability enables attackers to gain unauthorized access to system resources, escalate privileges, or completely compromise the affected system. The vulnerability affects not only individual applications but also system services that rely on ICU for text processing, making it a significant threat to overall system security and stability. Organizations running affected versions of Mac OS X face substantial risk of exploitation, particularly in environments where users may encounter malicious content through email attachments, web browsing, or file downloads.
Mitigation strategies for CVE-2011-0206 primarily focus on immediate system updates and patches provided by Apple to address the underlying buffer overflow in the ICU library. System administrators should prioritize updating to Mac OS X 10.6.8 or later versions where the vulnerability has been resolved through proper bounds checking and memory management improvements. Additionally, implementing network-based protections such as intrusion detection systems and monitoring for unusual string processing patterns can help detect potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute malicious code through compromised applications. Organizations should also consider implementing application whitelisting policies and restricting user privileges to minimize the potential impact of successful exploitation, particularly in environments where the vulnerability might be exploited through social engineering or compromised third-party applications.