CVE-2018-5852 in Snapdragon Automobile
Summary
by MITRE • 11/26/2024
An unsigned integer underflow vulnerability in IPA driver result into a buffer over-read while reading NAT entry using debugfs command 'cat /sys/kernel/debug/ipa/ip4_nat'
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Analysis
by VulDB Data Team • 01/10/2025
The vulnerability described in CVE-2018-5852 represents a critical security flaw within the IPA (IP Accelerator) driver component of certain mobile and embedded systems. This issue manifests as an unsigned integer underflow that occurs during the processing of NAT (Network Address Translation) entries through the debugfs interface. The IPA driver is responsible for hardware acceleration of network traffic on Qualcomm-based platforms, making this vulnerability particularly concerning for mobile device security and embedded network infrastructure. The vulnerability specifically impacts systems where the IPA driver handles NAT table operations and exposes these functionalities through the debugfs filesystem interface.
The technical root cause of this vulnerability stems from improper input validation within the IPA driver's NAT processing code. When a debugfs command attempts to read NAT entries from the ip4_nat file, the driver fails to properly validate the size parameter used in memory allocation operations. This allows an attacker to provide a crafted value that, when processed as an unsigned integer, results in an underflow condition. The underflow causes the driver to calculate an incorrect buffer size, leading to a subsequent buffer over-read when attempting to access memory locations beyond the allocated buffer boundaries. This memory corruption can result in arbitrary code execution or system instability, as the driver attempts to read from memory locations that may contain sensitive data or code segments.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides potential attack vectors for privilege escalation and system compromise. An attacker with access to the debugfs interface can exploit this condition to read arbitrary memory contents, potentially extracting sensitive information such as kernel memory addresses, cryptographic keys, or other confidential data. The vulnerability is particularly dangerous because it operates at kernel level, meaning successful exploitation can lead to complete system compromise without requiring additional privileges. This aligns with CWE-191, which specifically addresses unsigned integer underflow conditions, and represents a classic example of how improper integer handling can lead to memory safety violations.
The exploitation of this vulnerability requires access to the debugfs interface, which typically requires either physical access to the device or elevated privileges within the system. However, the attack surface is broadened by the fact that many embedded systems expose debug interfaces by default for diagnostic purposes. The attack vector follows patterns consistent with ATT&CK technique T1059.001, where adversaries leverage system commands and interfaces to execute malicious code. The vulnerability demonstrates how seemingly benign debugging features can become security risks when proper input validation and boundary checking are omitted from kernel-level code. Organizations should implement comprehensive security controls including disabling unnecessary debug interfaces, applying timely patches, and monitoring for suspicious memory access patterns in kernel modules.
Mitigation strategies for CVE-2018-5852 should focus on both immediate patching and long-term architectural improvements. The primary solution involves applying vendor-provided security patches that correct the integer underflow condition in the IPA driver code. These patches typically include proper input validation and boundary checking mechanisms that prevent the underflow from occurring during NAT entry processing. Additionally, system administrators should disable debugfs interfaces when not actively required for diagnostic purposes, as recommended by the principle of least privilege. Implementing kernel memory protection mechanisms such as stack canaries, address space layout randomization, and kernel address space protection can provide additional defense-in-depth measures. Regular security assessments of kernel modules and thorough code reviews focusing on integer handling and memory management should be conducted to prevent similar vulnerabilities from being introduced in future releases.