Improper Handling of Overlap Between Protected Memory Ranges

Opis

The product allows address regions to overlap, which can result in the bypassing of intended memory protection.

Isolated memory regions and access control (read/write) policies are used by hardware to protect privileged software. Software components are often allowed to change or remap memory region definitions in order to enable flexible and dynamically changeable memory management by system software.

If a software component running at lower privilege can program a memory address region to overlap with other memory regions used by software running at higher privilege, privilege escalation may be available to attackers. The memory protection unit (MPU) logic can incorrectly handle such an address overlap and allow the lower-privilege software to read or write into the protected memory region, resulting in privilege escalation attack. An address overlap weakness can also be used to launch a denial of service attack on the higher-privilege software memory regions.

Skutki

• Confidentiality, Integrity, Availability

  Modify Memory; Read Memory; DoS: Instability

Zapobieganie

• Architecture and Design

  Ensure that memory regions are isolated as intended and that access control (read/write) policies are used by hardware to protect privileged software.

• Implementation

  For all of the programmable memory protection regions, the memory protection unit (MPU) design can define a priority scheme.

  For example: if three memory regions can be programmed (Region_0, Region_1, and Region_2), the design can enforce a priority scheme, such that, if a system address is within multiple regions, then the region with the lowest ID takes priority and the access-control policy of that region will be applied. In some MPU designs, the priority scheme can also be programmed by trusted software.

  Hardware logic or trusted firmware can also check for region definitions and block programming of memory regions with overlapping addresses.

  The memory-access-control-check filter can also be designed to apply a policy filter to all of the overlapping ranges, i.e., if an address is within Region_0 and Region_1, then access to this address is only granted if both Region_0 and Region_1 policies allow the access.

  Skuteczność: High

Przykłady podatności

• CVE-2008-7096 virtualization product allows compromise of hardware product by accessing certain remapping registers.

Słabość nadrzędna

• CWE-284 Improper Access Control

Może prowadzić do

• CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

Kiedy powstaje

• Architecture and Design — Such issues could be introduced during hardware architecture and design or implementation and identified later during the Testing phase.
• Implementation

Dotyczy

Not Language-Specific, Not OS-Specific, Not Architecture-Specific, Memory Hardware, Processor Hardware

Uwagi

As of CWE 4.6, CWE-1260 and CWE-1316 are siblings under view 1000, but CWE-1260 might be a parent of CWE-1316. More analysis is warranted.

Źródła

1. The Memory Sinkhole — Christopher Domas, 2015
2. Hackatdac19 ariane_soc_pkg.sv — 2019
3. csr_regfile.sv — Florian Zaruba, Michael Schaffner, Andreas Traber, 2019