The bridge incorrectly translates security attributes from either trusted to untrusted or from untrusted to trusted when converting from one fabric protocol to another.

A bridge allows IP blocks supporting different fabric protocols to be integrated into the system. Fabric end-points or interfaces usually have dedicated signals to transport security attributes. For example, HPROT signals in AHB, AxPROT signals in AXI, and MReqInfo and SRespInfo signals in OCP.
The values on these signals are used to indicate the security attributes of the transaction. These include the immutable hardware identity of the controller initiating the transaction, privilege level, and type of transaction (e.g., read/write, cacheable/non-cacheable, posted/non-posted).
A weakness can arise if the bridge IP block, which translates the signals from the protocol used in the IP block endpoint to the protocol used by the central bus, does not properly translate the security attributes. As a result, the identity of the initiator could be translated from untrusted to trusted or vice-versa. This could result in access-control bypass, privilege escalation, or denial of service.

Primary

Resultant

Architecture and Design

Implementation

Confidentiality
Integrity
Access Control
Modify Memory
Read Memory
Gain Privileges or Assume Identity
Bypass Protection Mechanism
Execute Unauthorized Code or Commands

Architecture and Design
The translation must map signals in such a way that untrusted agents cannot map to trusted agents or vice-versa.

Implementation
Ensure that the translation maps signals in such a way that untrusted agents cannot map to trusted agents or vice-versa.

The bridge interfaces between OCP and AHB end points. OCP uses MReqInfo signal to indicate security attributes, whereas AHB uses HPROT signal to indicate the security attributes. The width of MReqInfo can be customized as needed. In this example, MReqInfo is 5-bits wide and carries the privilege level of the OCP controller.
The values 5'h11, 5'h10, 5'h0F, 5'h0D, 5'h0C, 5'h0B, 5'h09, 5'h08, 5'h04, and 5'h02 in MReqInfo indicate that the request is coming from a privileged state of the OCP bus controller. Values 5'h1F, 5'h0E, and 5'h00 indicate untrusted, privilege state.
Though HPROT is a 5-bit signal, we only consider the lower, two bits in this example. HPROT values 2'b00 and 2'b10 are considered trusted, and 2'b01 and 2'b11 are considered untrusted.
The OCP2AHB bridge is expected to translate trusted identities on the controller side to trusted identities on the responder side. Similarly, it is expected to translate untrusted identities on the controller side to untrusted identities on the responder side.

module ocp2ahb
(

ahb_hprot,
ocp_mreqinfo

);

output [1:0] ahb_hprot; // output is 2 bit signal for AHB HPROT
input [4:0] ocp_mreqinfo; // input is 5 bit signal from OCP MReqInfo
wire [6:0] p0_mreqinfo_o_temp; // OCP signal that transmits hardware identity of bus controller

wire y;

reg [1:0] ahb_hprot;

// hardware identity of bus controller is in bits 5:1 of p0_mreqinfo_o_temp signal
assign p0_mreqinfo_o_temp[6:0] = {1'b0, ocp_mreqinfo[4:0], y};

always @*
begin

case (p0_mreqinfo_o_temp[4:2])

000: ahb_hprot = 2'b11; // OCP MReqInfo to AHB HPROT mapping
001: ahb_hprot = 2'b00;
010: ahb_hprot = 2'b00;
011: ahb_hprot = 2'b01;
100: ahb_hprot = 2'b00;
101: ahb_hprot = 2'b00;
110: ahb_hprot = 2'b10;
111: ahb_hprot = 2'b00;

endcase

end
endmodule

Logic in the case statement only checks for MReqInfo bits 4:2, i.e., hardware-identity bits 3:1. When ocp_mreqinfo is 5'h1F or 5'h0E, p0_mreqinfo_o_temp[2] will be 1. As a result, untrusted IDs from OCP 5'h1F and 5'h0E get translated to trusted ahb_hprot values 2'b00.

Allowed
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Arun Kanuparthi, Hareesh Khattri, Parbati Manna
Intel Corporation
2020-05-24
4.3
2020-12-10

CWE Content Team
MITRE
2022-10-13
updated Demonstrative_Examples

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Weakness_Ordinalities

Hareesh Khattri
Intel Corporation
2022-04-28
Corrections in the demonstrative example.