CVE-2014-8159

What it actually does

The InfiniBand user verbs implementation fails to restrict memory region registration, allowing a local process with access to a uverbs device to map arbitrary physical memory addresses and thereby read or write kernel or user memory.

Why it matters to the business

Local attackers can crash production systems or obtain full root privileges, leading to unplanned downtime, data theft, or persistent unauthorized access across Linux server fleets.

How an attack unfolds

An attacker obtains a local shell on an affected Linux host, locates the InfiniBand uverbs device node, and issues a sequence of user verbs calls that bypass the intended memory registration checks, resulting in direct physical memory access that can be used for privilege escalation or denial of service.

How to fix it

Upgrade the Linux kernel to a version containing the memory registration restriction fix (RHEL 6: 2.6.32-504.12.2 or later; apply equivalent updates from Canonical, Debian, or other distributions). Disable or restrict access to InfiniBand uverbs devices when the hardware is not required.

How to confirm the fix worked

Verify installed kernel version meets or exceeds the fixed release for each distribution, confirm that uverbs device nodes are either absent or protected by appropriate permissions, and run vendor-supplied regression tests for InfiniBand user verbs.

Typical attack path

1. Obtain local unprivileged shell on target Linux system
2. Confirm presence of /dev/infiniband/uverbs* device node and required permissions
3. Craft and execute user verbs calls that register memory regions outside allowed bounds
4. Use resulting arbitrary physical memory mapping to read kernel structures or inject code
5. Escalate to root or trigger kernel panic

How to detect it

Review authentication and process execution logs for unexpected local sessions followed by access to /dev/infiniband/uverbs devices; correlate with kernel oops or panic messages indicating invalid memory access; inspect auditd records for unusual mmap or ibv calls from non-privileged users.

• /dev/infiniband/uverbs
• ibv_reg_mr
• unexpected kernel oops referencing infiniband
• process accessing /dev/infiniband immediately before privilege escalation

What your security team should do

• Prioritize kernel updates on all systems exposing InfiniBand hardware or uverbs devices
• Audit local user permissions on /dev/infiniband/* and remove unnecessary access
• Monitor for new kernel releases and schedule staged rollouts within 30 days
• Disable InfiniBand user verbs functionality via modprobe blacklist where hardware is unused