CWE-1312: Missing Protection for Mirrored Regions in On-Chip Fabric Firewall

What is Missing Protection for Mirrored Regions in On-Chip Fabric Firewall?

• Overview: The vulnerability involves a failure to protect mirrored regions in on-chip fabric firewalls, which are used for redundancy and fault tolerance. These regions should be protected just like the main memory regions to prevent unauthorized access.

• Exploitation Methods:

• Attackers can exploit this vulnerability by accessing mirrored memory regions to bypass existing protections on the main memory.
• Common attack patterns include reading from or writing to mirrored regions to leak or corrupt data.

• Security Impact:

• Direct consequences include unauthorized access to sensitive data and potential data corruption.
• Potential cascading effects involve undermining system reliability and exposing other vulnerabilities.
• Business impact includes loss of data integrity, potential data breaches, and damage to reputation.

• Prevention Guidelines:

• Ensure that any security policies applied to the main memory regions are also enforced on mirrored regions.
• Implement comprehensive access controls and auditing for both main and mirrored memory regions.
• Regularly review and update security configurations and use automated tools to detect unprotected mirrored regions.

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Technical Details

Likelihood of Exploit: Not specified

Affected Languages: Not Language-Specific

Affected Technologies: Not Technology-Specific

Vulnerable Code Example

class OnChipFirewall:
    def __init__(self):
        self.protected_regions = [(0x0000, 0x1000)]  # Main protected region
        self.mirrored_regions = [(0x0000, 0x1000), (0x1000, 0x2000)]  # Mirrored regions not protected

    def access_memory(self, address):
        # Only checks the main protected region, not the mirrored one
        if any(start <= address < end for start, end in self.protected_regions):
            print("Access denied to protected region")
            return False
        print("Access granted")
        return True

# Usage
firewall = OnChipFirewall()
firewall.access_memory(0x1500)  # Incorrectly grants access to a mirrored region

Explanation:

• The OnChipFirewall class is designed to protect certain memory regions from unauthorized access.
• The protected_regions list specifies regions that are protected, but the mirrored_regions list, which should be equally protected, is not checked in the access_memory method.
• As a result, when accessing the address 0x1500, which falls within a mirrored region, access is incorrectly granted due to the missing protection check for mirrored regions.

How to fix Missing Protection for Mirrored Regions in On-Chip Fabric Firewall?

To fix this vulnerability, ensure that all mirrored regions receive the same protection as the main addressed region. This can be done by expanding the protection checks to include all mirrored memory or MMIO regions. Implement an additional mechanism to correctly identify and protect access to these mirrored regions.

Fix Approach:

1. Combine the protected_regions and mirrored_regions into a single list of regions to protect.
2. Modify the access control logic to verify if the address falls within any of these regions before granting access.

Fixed Code Example

class OnChipFirewall:
    def __init__(self):
        # Combine main and mirrored regions into a single list of protected regions
        self.protected_regions = [(0x0000, 0x1000), (0x1000, 0x2000)]

    def access_memory(self, address):
        # Check both main and mirrored protected regions
        if any(start <= address < end for start, end in self.protected_regions):
            print("Access denied to protected region")
            return False
        print("Access granted")
        return True

# Usage
firewall = OnChipFirewall()
firewall.access_memory(0x1500)  # Correctly denies access to the protected mirrored region

Explanation:

• The protected_regions list now includes both the main and mirrored regions, ensuring comprehensive protection.
• The access_memory method checks all defined protected regions, correctly denying access to any address within both the main and mirrored protected regions.
• This approach ensures that access controls are consistent across all memory regions, effectively mitigating the vulnerability by ensuring no unauthorized access to any protected or mirrored region.