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SYNTHESIS OF THE VULNERABILITY

An attacker located inside a KVM guest system can read or access
memory with elevated privileges.

Severity: 2/4

Consequences: administrator access/rights, privileged
access/rights, data reading, data creation/edition

Provenance: user shell

Means of attack: no proof of concept, no attack

Ability of attacker: expert (4/4)

Confidence: confirmed by the editor (5/5)

Diffusion of the vulnerable configuration: high (3/3)

Creation date: 09/02/2010

IMPACTED PRODUCTS

– Debian Linux
– Linux kernel
– Red Hat Enterprise Linux

DESCRIPTION OF THE VULNERABILITY

A x86 processor has 4 rings associated to privileges:
– ring 0 : all memory accesses and all assembler instructions are
allowed
– ring 3 : memory access is restricted to segments with the same
privilege level

The gva_to_gpa() function of the KVM arch/x86/kvm/emulate.c
emulator does not check the CPL (Current Privilege Level) before
doing a memory operation.

An attacker located inside a KVM guest system can therefore read
or access memory with elevated privileges.

CHARACTERISTICS

Identifiers: 559091, BID-38158, CVE-2010-0298, DSA-1996-1,
RHSA-2010:0088-02, VIGILANCE-VUL-9422

http://vigilance.fr/vulnerability/Linux-kernel-memory-access-in-KVM-9422