Intelligent Platform Management Interface (IPMI) is a set of standardized specifications for hardware-based host management systems used for system management and monitoring. It acts as an autonomous subsystem and works independently of the host's BIOS, CPU, firmware, and underlying operating system. IPMI provides sysadmins with the ability to manage and monitor systems even if they are powered off or in an unresponsive state. It operates using a direct network connection to the system's hardware and does not require access to the operating system via a login shell. IPMI can also be used for remote upgrades to systems without requiring physical access to the target host.
Systems that use the IPMI protocol are called Baseboard Management Controllers (BMCs). BMCs are typically implemented as embedded ARM systems running Linux, and connected directly to the host's motherboard. BMCs are built into many motherboards but can also be added to a system as a PCI card. Most servers either come with a BMC or support adding a BMC. The most common BMCs we often see during internal penetration tests are HP iLO, Dell DRAC, and Supermicro IPMI. If we can access a BMC during an assessment, we would gain full access to the host motherboard and be able to monitor, reboot, power off, or even reinstall the host operating system. Gaining access to a BMC is nearly equivalent to physical access to a system. Many BMCs (including HP iLO, Dell DRAC, and Supermicro IPMI) expose a web-based management console, some sort of command-line remote access protocol such as Telnet or SSH, and the port 623 UDP, which, again, is for the IPMI network protocol.
Port
623 UDP
IPMI
Attacks
Default Password
Product
Username
Password
Dell iDRAC
root
calvin
HP iLO
Administrator
randomized 8-character string consisting of numbers and uppercase letters
Supermicro IPMI
ADMIN
ADMIN
Brute force password thanks to RAKP in IPMI 2.0
During the authentication process, the server sends a salted SHA1 or MD5 hash of the user's password to the client before authentication takes place. This can be leveraged to obtain the password hash for ANY valid user account on the BMC. These password hashes can then be cracked offline using a dictionary attack using Hashcat mode 7300.
# For HP iLOhashcat-m7300ipmi.txt-a3?1?1?1?1?1?1?1?1-1?d?u
Also possible to use the following metasploit module to retrieve IPMI hashes and for cracking