CVE-2019-15877 in FreeBSD
Summary
by MITRE
In FreeBSD 12.1-STABLE before r356606 and 12.1-RELEASE before 12.1-RELEASE-p3, driver specific ioctl command handlers in the ixl network driver failed to check whether the caller has sufficient privileges allowing unprivileged users to trigger updates to the device's non-volatile memory.
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Analysis
by VulDB Data Team • 10/14/2020
The vulnerability identified as CVE-2019-15877 affects FreeBSD operating systems versions 12.1-STABLE prior to revision 356606 and 12.1-RELEASE prior to patch level 12.1-RELEASE-p3. This issue resides within the ixl network driver which manages Intel Ethernet network adapters. The core problem manifests in the driver's ioctl command handling mechanism where insufficient privilege validation occurs during specific device configuration operations. The ixl driver is responsible for managing network interface cards that support Intel's 10 Gigabit Ethernet controllers and related hardware components.
The technical flaw represents a privilege escalation vulnerability classified under CWE-276, specifically concerning improper privilege management in device driver operations. When the ixl driver processes certain ioctl commands, it fails to verify whether the calling process possesses the necessary administrative privileges required for modifying non-volatile memory components of the network hardware. This oversight allows any unprivileged user account to execute ioctl commands that would normally require root-level access or administrative permissions. The vulnerability specifically impacts the device's non-volatile memory updates, which typically contain firmware, configuration parameters, or other persistent data stored in read-only memory sections of the network adapter.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables unauthorized modification of critical network hardware components. An attacker with local access could potentially corrupt firmware images, alter network configuration settings, or manipulate device behavior in ways that could disrupt network communications or create persistent backdoors. The vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation through improper privilege management, and T1547.001, covering registry run keys and startup folder modifications. Additionally, this issue falls under the broader category of device driver security flaws that can compromise system integrity and availability.
Mitigation strategies should prioritize immediate system updates to FreeBSD versions 12.1-RELEASE-p3 or later, which contain the patched ioctl validation mechanisms. System administrators should also implement additional security controls such as restricting local user access to network device interfaces and monitoring for unauthorized ioctl command executions. The patch addresses the core issue by adding proper privilege checks before allowing access to non-volatile memory modification operations. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of such vulnerabilities. Regular security assessments of device drivers and kernel modules remain essential for maintaining system security posture, particularly for network-facing components that handle direct hardware access operations.