BMC Firmware Flaws

Over a dozen security flaws have been discovered in baseboard management controller (BMC) firmware from Lanner that could expose operational technology (OT) and internet of things (IoT) networks to remote attacks.

BMC refers to a specialized service processor, a system-on-chip (SoC), that's found in server motherboards and is used for remote monitoring and management of a host system, including performing low-level system operations such as firmware flashing and power control.

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Nozomi Networks, which analyzed an Intelligent Platform Management Interface (IPMC) from Taiwanese vendor Lanner Electronics, said it uncovered 13 weaknesses affecting IAC-AST2500.

All the issues affect version 1.10.0 of the standard firmware, with the exception of CVE-2021-4228, which impacts version 1.00.0. Four of the flaws (from CVE-2021-26727 to CVE-2021-26730) are rated 10 out of 10 on the CVSS scoring system.

BMC Firmware Flaws

In particular, the industrial security company found that CVE-2021-44467, an access control bug in the web interface, could be chained with CVE-2021-26728, a buffer overflow flaw, to achieve remote code execution on the BMC with root privileges.

"When also considering that all processes run with root privileges on the device, the combined weaknesses enable an unauthenticated attacker to completely compromise both the BMC and the managed host," the company said in a write-up published last week.

Lanner has since released an updated firmware that addresses the vulnerabilities in question following responsible disclosure.

"BMCs represent an attractive way to conveniently monitor and manage computer systems without requiring physical access, in the IT as well as in the OT/IoT domain," the researchers said.

"Nevertheless, their usability comes at the expense of a broader attack surface, and that may lead to an increase of the overall risk if they are not adequately protected."


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