CVE-2016-8733 in SmartOS
Summary
by MITRE
An exploitable integer 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 kernel panic and potentially be leveraged into a full privilege escalation vulnerability. This vulnerability is distinct from CVE-2016-9031.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/08/2022
The CVE-2016-8733 vulnerability represents a critical integer overflow flaw within the Joyent SmartOS hypervisor file system implementation known as Hyprlofs. This vulnerability specifically manifests in the Ioctl system call handling for the HYPRLOFS_ADD_ENTRIES command when processing native file systems. The flaw arises from inadequate input validation and overflow protection mechanisms within the kernel-level file system driver, creating a pathway for malicious input manipulation that can result in system instability and potential privilege escalation. The vulnerability exists in the 20161110T013148Z version of SmartOS, indicating a specific release that contained this exploitable condition within its hypervisor file system implementation.
The technical exploitation of this vulnerability occurs through a carefully crafted Ioctl command sequence that triggers an integer overflow condition during the processing of file system entries. When the HYPRLOFS_ADD_ENTRIES command receives malformed input parameters, the integer overflow corrupts kernel memory structures and can lead to a kernel panic, effectively crashing the operating system. This type of vulnerability falls under CWE-190, Integer Overflow or Wraparound, which is a well-documented weakness in software systems where integer arithmetic operations produce results that exceed the maximum value representable by the data type. The overflow condition specifically impacts the kernel's memory management and file system entry handling mechanisms, creating a potential attack surface for privilege escalation.
The operational impact of this vulnerability extends beyond simple system instability to encompass potential full system compromise and privilege escalation. A successful exploitation can result in a kernel panic that brings the entire system to a halt, while the underlying integer overflow condition may provide attackers with opportunities to manipulate kernel memory and potentially execute arbitrary code with the highest system privileges. The vulnerability is particularly concerning in virtualized environments where SmartOS hypervisors manage multiple guest operating systems, as an attacker could potentially leverage this condition to escape virtual machine boundaries and gain control over the host system. This aligns with ATT&CK technique T1068, Exploitation for Privilege Escalation, where attackers exploit software vulnerabilities to gain elevated privileges.
Mitigation strategies for CVE-2016-8733 should focus on immediate patching of the SmartOS hypervisor to address the integer overflow condition in the Hyprlofs file system driver. System administrators should ensure that all Joyent SmartOS installations are updated to versions that contain the appropriate kernel fixes for this vulnerability. Network segmentation and access controls should be implemented to limit exposure of affected systems to untrusted networks or users. Additionally, monitoring systems should be configured to detect anomalous Ioctl command sequences that might indicate exploitation attempts. The vulnerability's distinct nature from CVE-2016-9031 indicates that while both affect SmartOS hypervisor components, they require separate remediation approaches, making comprehensive vulnerability management essential for protecting against both threats. Organizations should also implement regular security assessments of their virtualization environments to identify similar integer overflow conditions in other kernel components and file systems that may present similar attack vectors.