An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. DMA attacks on the AhciBusDxe shared buffer used by SMM and non-SMM code could cause TOCTOU race-condition issues that could lead to corruption of SMRAM and escalation of privileges. This attack can be mitigated using IOMMU protection for the ACPI runtime memory used for the command buffer. This attack can be mitigated by copying the firmware block services data to SMRAM before checking it.

An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. DMA attacks on the VariableRuntimeDxe shared buffer used by SMM and non-SMM code could cause TOCTOU race-condition issues that could lead to corruption of SMRAM and escalation of privileges. This issue was fixed in the kernel, which also protected chipset and OEM chipset code.

An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. DMA attacks on the StorageSecurityCommandDxe shared buffer used by SMM and non-SMM code could cause TOCTOU race-condition issues that could lead to corruption of SMRAM and escalation of privileges. This attack can be mitigated using IOMMU protection for the ACPI runtime memory used for the command buffer. This attack can be mitigated by copying the firmware block services data to SMRAM before checking it.

An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. DMA attacks on the HddPassword shared buffer used by SMM and non-SMM code could cause TOCTOU race-condition issues that could lead to corruption of SMRAM and escalation of privileges. This attack can be mitigated using IOMMU protection for the ACPI runtime memory used for the command buffer. This attack can be mitigated by copying the firmware block services data to SMRAM before checking it.

** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a security issue. Notes: none.

An issue was discovered in IhisiSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. The IhisiDxe driver uses the command buffer to pass input and output data. By modifying the command buffer contents with DMA after the input parameters have been checked but before they are used, the IHISI SMM code may be convinced to modify SMRAM or OS, leading to possible data corruption or escalation of privileges.