CVE-2016-9035 in SmartOS
Summary
by MITRE
An exploitable buffer overflow exists in the Joyent SmartOS 20161110T013148Z Hyprlofs file system. The vulnerability is present in the Ioctl system call with the command HYPRLOFS_ADD_ENTRIES when dealing with native file systems. An attacker can craft an input that can cause a buffer overflow in the path variable leading to an out of bounds memory access and could result in potential privilege escalation. This vulnerability is distinct from CVE-2016-9033.
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Analysis
by VulDB Data Team • 10/08/2022
The CVE-2016-9035 vulnerability represents a critical buffer overflow flaw within the Joyent SmartOS hypervisor filesystem implementation, specifically affecting the Hyprlofs file system version 20161110T013148Z. This vulnerability manifests in the Ioctl system call interface when processing the HYPRLOFS_ADD_ENTRIES command, creating a dangerous condition where malformed input can trigger memory corruption. The flaw occurs during native filesystem operations, making it particularly concerning for system administrators managing virtualized environments where SmartOS serves as the underlying hypervisor platform.
The technical implementation of this vulnerability stems from inadequate input validation within the path variable handling mechanism of the Ioctl subsystem. When the HYPRLOFS_ADD_ENTRIES command processes user-supplied data, the system fails to properly bounds-check the input buffer before copying data into internal storage structures. This allows an attacker to provide oversized input that exceeds the allocated buffer size, resulting in memory overwrite conditions that can corrupt adjacent memory regions. The vulnerability specifically targets the path variable processing logic, where the system attempts to store file system path information without proper size enforcement, creating a classic buffer overflow scenario that can be exploited through crafted ioctl calls.
The operational impact of this vulnerability extends beyond simple memory corruption, as it presents a potential privilege escalation vector within the SmartOS hypervisor environment. An attacker who successfully exploits this buffer overflow can manipulate memory contents to execute arbitrary code with elevated privileges, potentially gaining root access to the underlying hypervisor system. This creates a significant risk for cloud environments and virtualized infrastructures where SmartOS is deployed, as compromise of the hypervisor level can lead to complete system takeover and affect all virtual machines running on that platform. The vulnerability's distinct nature from CVE-2016-9033 indicates it operates through different code paths, making it more challenging to address comprehensively and requiring specific mitigation strategies.
Security professionals should approach this vulnerability through multiple defensive layers, beginning with immediate patching of affected SmartOS versions and implementing strict input validation controls at the system call interface level. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and can be mapped to ATT&CK technique T1055 for privilege escalation through kernel-level exploitation. Organizations should also implement monitoring for unusual ioctl activity patterns and consider deploying intrusion detection systems that can identify potential exploitation attempts. Given the hypervisor-level nature of this vulnerability, additional network segmentation measures and privileged access controls should be enforced to limit potential attack surface. The exploitability of this vulnerability underscores the importance of maintaining current security patches and conducting regular vulnerability assessments of virtualization platforms to prevent similar issues from compromising system integrity.