Intel has warned that some of its motherboards contain a flaw in their BIOS setup that creates a privilege escalation vulnerability.
As a result of the security bug, users already logged in as administrators could change code running in System Management Mode. SMM is a privileged operating environment that operates outside of operating system control, creating a possible mechanism (at least in theory) for mounting rootkit-style attacks on vulnerable systems.
Exploiting the bug would probably require physical access to affected systems, a fair amount of skill and not a little luck in locating a vulnerable box.
Desktop and server systems are both potentially affected by the bug, described by Intel as "important", so the flaw still merits close attention.
BIOS updates designed to mitigate against attack are available for vulnerable Intel motherboards, as explained in an advisory by the chip giant issued on Wednesday.
Intel lists the following desktop motherboards as potentially vulnerable: D5400XS, DX58SO, DX48BT2, DX38BT, DP45SG, DQ45CB, DQ45EK, DQ43AP, DB43LD, DG41MJ, DG41RQ, DG41TY, DG45ID, DG45FC, DG43NB, DP43TF, DQ35JO, DQ35MP, DG33BU, DG33FB, DG33TL, DP35DP, D945GSEJT, D945GCLF, D945GCLF2.
Intel Server Boards in the S3000, S3200, S5000 series, S5400 series, and S5500 series also need a BIOS update.
BIOS-related security flaws are rare but not unprecedented. The latest bug was discovered by researchers from Invisible Things Lab. Last year, the same researchers detailed a high-privilege rootkit vulnerability in Xen hypervisor that Intel addressed via a Bios update.
Invisible Things is due to present new research on attacking Intel BIOS at this week's Black Hat conference in Las Vegas, which is likely to be dominated by a detailed dissection of the issues arising from Intel's latest BIOS security advisory. ®