BMC
Baseboard Management Controller
A small computer on the board that manages the server remotely.
Where It Sits
The small stack marks its layer. Beside it, each related technology links to its own page.
- App
- Framework
- Web Server
- Runtime
- Containers
- OS
- Hypervisor
- FirmwareBMC
- Hardware
- Data
About
A BMC is a small, always-on computer built into a server board that lets administrators manage the machine remotely, even when it is powered off. Dell calls its version iDRAC and HPE calls its iLO. It has its own network address and web interface, which makes it a target if it is exposed.
How to Spot It
These are signs that a system runs BMC, seen from outside without signing in, such as a response header, a cookie, a path or a default port. They help you find where it runs across your own estate. A version shown to the world also tells anyone scanning which flaws might apply, so it is worth hiding.
- Path
/redfish/v1/- Default port
623 (IPMI, UDP)- Page source
Integrated Lights-Out
If It Has a Flaw
The BMC can power the server on and off, mount disk images and reach the operating system, all through its own network port, separate from the server's own connections. An exposed or unpatched BMC is close to physical access over the network.
Nothing runs on it, but it controls the machine it is built into.
Well-Known Flaws
Each flaw has a CVE id, the unique number a publicly known vulnerability is given so that every advisory names the same flaw. The id links to the advisory, and the card says what the flaw let an attacker do and how far it reached because of where BMC sits.
CVE-2017-12542 (opens in a new tab)2017
iLO 4 Authentication Bypass
A flaw in HPE iLO 4 let attackers bypass login and run code on the management controller.
Reach It gave control of the server over the network, through its management port.
Stacks and Code
Its code arrives from the sources listed, and each source's page says how bad code could get in through it.
- Its Code Comes From
- Vendor Updates