CVE-2014-4422 in Mac OS X
Summary
by MITRE
The kernel in Apple iOS before 8 and Apple TV before 7 uses a predictable random number generator during the early portion of the boot process, which allows attackers to bypass certain kernel-hardening protection mechanisms by using a user-space process to observe data related to the random numbers.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 02/23/2022
The vulnerability identified as CVE-2014-4422 represents a critical weakness in Apple's kernel security implementation across iOS versions prior to 8 and Apple TV versions prior to 7. This flaw stems from the use of a predictable random number generator during the early boot phase, a period when the system establishes critical security parameters and hardening mechanisms. The issue fundamentally compromises the integrity of cryptographic operations and security protections that rely on randomness for their effectiveness. During the boot process, the kernel generates random numbers to create security tokens, encryption keys, and other protective mechanisms that should remain unpredictable to adversaries. However, when attackers can observe and correlate data from user-space processes, they gain sufficient information to predict the kernel's random number generation sequence, thereby undermining the security model.
This vulnerability specifically targets the kernel's early boot phase where random number generation is critical for establishing security boundaries and protection mechanisms. The predictable nature of the random number generator allows attackers to bypass kernel hardening protections such as stack canaries, address space layout randomization, and other security features that depend on unpredictable entropy. The attack vector involves a user-space process observing data related to random number generation, which provides enough information to reconstruct the kernel's random sequence. This represents a significant bypass of security controls that are fundamental to modern operating system security models, particularly those implemented under the principle of least privilege and defense in depth.
The operational impact of CVE-2014-4422 extends beyond simple privilege escalation to encompass complete bypass of kernel security mechanisms that protect against various attack vectors. Attackers can leverage this vulnerability to predict security parameters used in kernel memory management, which could enable them to craft exploits that circumvent stack canary protections, bypass kernel address space layout randomization, and potentially gain unauthorized access to kernel memory regions. The vulnerability's severity is amplified by its timing during the boot process, when the system is most vulnerable and when security controls are being established. This aligns with ATT&CK framework technique T1068 which describes privilege escalation through kernel exploits, and CWE-330 which addresses insufficient entropy in random number generation. The vulnerability essentially provides attackers with a backdoor into the kernel's security infrastructure, allowing them to operate with elevated privileges and access protected system resources.
Mitigation strategies for CVE-2014-4422 primarily involve updating to patched versions of iOS 8 and Apple TV 7, which address the predictable random number generation issue through improved entropy sources and timing mechanisms during the boot process. System administrators should also implement monitoring for unusual patterns in random number generation and establish robust entropy collection mechanisms. The vulnerability highlights the importance of proper random number generation in security-critical systems and underscores the need for comprehensive entropy sources during system initialization. Organizations should also consider implementing additional security controls such as kernel patch protection, secure boot mechanisms, and regular security audits to prevent similar vulnerabilities from being exploited in other system components. This vulnerability serves as a reminder of the critical importance of entropy quality in cryptographic security implementations and the potential consequences when predictable random number generation is used in security-sensitive contexts.