CVE-2015-5840 in Watch
Summary
by MITRE
The checkint division routines in removefile in Apple iOS before 9 allow attackers to cause a denial of service (overflow fault and app crash) via crafted data.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2015-5840 resides within the removefile function of Apple iOS systems prior to version 9, specifically affecting the checkint division routines during file removal operations. This flaw represents a classic buffer overflow condition that manifests when the system processes crafted data through the file removal pathway. The vulnerability is particularly concerning as it operates at a low-level system function that handles file operations, making it accessible through common file manipulation activities. The affected checkint division routines are responsible for processing integer values during the file removal process, where improper input validation leads to arithmetic overflow conditions that ultimately result in system instability.
The technical implementation of this vulnerability exploits the absence of proper bounds checking within the integer division operations performed by the removefile function. When maliciously crafted data is passed to the file removal routine, the system's integer handling code fails to properly validate input parameters, leading to overflow conditions that cause the application to fault and crash. This behavior aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and demonstrates how improper integer handling can lead to denial of service attacks. The vulnerability operates through the system's file management subsystem, leveraging the fact that file removal operations are fundamental to system operation and frequently executed by both legitimate applications and user processes.
The operational impact of CVE-2015-5840 extends beyond simple application crashes to encompass broader system reliability concerns within iOS environments. Attackers can exploit this vulnerability to repeatedly crash applications that utilize file removal functionality, effectively creating a persistent denial of service condition that degrades system performance and user experience. The vulnerability's accessibility through normal file operations means that even routine system activities could trigger the overflow condition, making it particularly dangerous in environments where automated processes or user interactions might inadvertently provide the malicious input. This type of vulnerability is classified under the MITRE ATT&CK framework as a Denial of Service technique, specifically targeting system resources through exploitation of software flaws.
Mitigation strategies for CVE-2015-5840 require immediate system updates to iOS version 9 or later, where Apple implemented proper bounds checking and integer overflow protections within the file removal routines. Organizations should also consider implementing network-level protections to monitor for suspicious file operations and establish robust patch management procedures to ensure timely deployment of security updates. System administrators should conduct vulnerability assessments to identify any custom applications that might be using vulnerable file removal functions and ensure these applications are updated or patched accordingly. The remediation process aligns with standard cybersecurity practices outlined in NIST SP 800-128 for vulnerability management and incident response, emphasizing the importance of timely patch deployment and system hardening measures to prevent exploitation of integer overflow conditions.