Perform a security evaluation of system-level architecture and design with software-aided physical attacks in scope.
CWE-1256 Base Stable
Improper Restriction of Software Interfaces to Hardware Features
This vulnerability occurs when a system's software interfaces to hardware features—like power, clock, or performance management—are not properly locked down. This allows attackers to misuse these…
Definition
What is CWE-1256?
This vulnerability occurs when a system's software interfaces to hardware features—like power, clock, or performance management—are not properly locked down. This allows attackers to misuse these interfaces from software to tamper with hardware memory or registers, or to gather sensitive data by observing physical side effects, without needing physical access to the device.
Many developers assume that attacks like fault injection or side-channel analysis require an attacker to physically touch the device. This assumption breaks down when software can directly control hardware features like voltage, clock speed, or power meters. Attackers can exploit these poorly restricted interfaces from a standard application to deliberately cause bit errors (faults) or to measure power consumption patterns, leading to privilege escalation, authentication bypass, or cryptographic key extraction.
Common examples include abusing dynamic voltage and frequency scaling (DVFS) to induce faults, using hardware power meters (e.g., Intel RAPL) for side-channel analysis, or triggering Rowhammer-style bit flips via rapid memory accesses. Managing this at scale is difficult; an ASPM like Plexicus can help you track and remediate these hardware-interface flaws across your entire stack, correlating code patterns with potential runtime exploitation.
Real-world impact
Real-world CVEs caused by CWE-1256
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Plundervolt: Improper conditions check in voltage settings for some Intel(R) Processors may allow a privileged user to potentially enable escalation of privilege and/or information disclosure via local access [REF-1081].
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PLATYPUS Attack: Insufficient access control in the Linux kernel driver for some Intel processors allows information disclosure.
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Observable discrepancy in the RAPL interface for some Intel processors allows information disclosure.
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AMD extension to a Linux service does not require privileged access to the RAPL interface, allowing side-channel attacks.
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NaCl in 2015 allowed the CLFLUSH instruction, making Rowhammer attacks possible.
How attackers exploit it
Step-by-step attacker path
- 1
This example considers the Rowhammer problem [REF-1083]. The Rowhammer issue was caused by a program in a tight loop writing repeatedly to a location to which the program was allowed to write but causing an adjacent memory location value to change.
- 2
Preventing the loop required to defeat the Rowhammer exploit is not always possible:
- 3
While the redesign may be possible for new devices, a redesign is not possible in existing devices. There is also the possibility that reducing capacitance with a relayout would impact the density of the device resulting in a less capable, more costly device.
- 4
Suppose a hardware design implements a set of software-accessible registers for scaling clock frequency and voltage but does not control access to these registers. Attackers may cause register and memory changes and race conditions by changing the clock or voltage of the device under their control.
- 5
Consider the following SoC design. Security-critical settings for scaling clock frequency and voltage are available in a range of registers bounded by [PRIV_END_ADDR : PRIV_START_ADDR] in the tmcu.csr module in the HW Root of Trust. These values are writable based on the lock_bit register in the same module. The lock_bit is only writable by privileged software running on the tmcu.
Vulnerable code example
Vulnerable Other
This example considers the Rowhammer problem [REF-1083]. The Rowhammer issue was caused by a program in a tight loop writing repeatedly to a location to which the program was allowed to write but causing an adjacent memory location value to change.
Continuously writing the same value to the same address causes the value of an adjacent location to change value. Secure code example
Secure Other
Preventing the loop required to defeat the Rowhammer exploit is not always possible:
Redesign the RAM devices to reduce inter capacitive coupling making the Rowhammer exploit impossible. What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-1256
- Architecture and Design / Implementation Ensure proper access control mechanisms protect software-controllable features altering physical operating conditions such as clock frequency and voltage.
Detection signals
How to detect CWE-1256
Use custom software to change registers that control clock settings or power settings to try to bypass security locks, or repeatedly write DRAM to try to change adjacent locations. This can be effective in extracting or changing data. The drawback is that it cannot be run before manufacturing, and it may require specialized software.
CWE-1256
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Frequently asked questions What is CWE-1256?
How serious is CWE-1256?
What languages or platforms are affected by CWE-1256?
How can I prevent CWE-1256?
How does Plexicus detect and fix CWE-1256?
Where can I learn more about CWE-1256?
Frequently asked questions
What is CWE-1256?
This vulnerability occurs when a system's software interfaces to hardware features—like power, clock, or performance management—are not properly locked down. This allows attackers to misuse these interfaces from software to tamper with hardware memory or registers, or to gather sensitive data by observing physical side effects, without needing physical access to the device.
How serious is CWE-1256?
MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.
What languages or platforms are affected by CWE-1256?
MITRE lists the following affected platforms: Not OS-Specific, Not Architecture-Specific, Not Technology-Specific, Memory Hardware, Power Management Hardware, Clock/Counter Hardware.
How can I prevent CWE-1256?
Ensure proper access control mechanisms protect software-controllable features altering physical operating conditions such as clock frequency and voltage.
How does Plexicus detect and fix CWE-1256?
Plexicus's SAST engine matches the data-flow signature for CWE-1256 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-1256?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/1256.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-1256
CWE-285 Parent
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CWE-1230 Sibling
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CWE-1297 Sibling
Unprotected Confidential Information on Device is Accessible by OSAT Vendors
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CWE-1328 Sibling
Security Version Number Mutable to Older Versions
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CWE-552 Sibling
Files or Directories Accessible to External Parties
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CWE-732 Sibling
Incorrect Permission Assignment for Critical Resource
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CWE-862 Sibling
Missing Authorization
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CWE-863 Sibling
Incorrect Authorization
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CWE-926 Sibling
Improper Export of Android Application Components
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Resources
Further reading
- MITRE — official CWE-1256 https://cwe.mitre.org/data/definitions/1256.html
- Plundervolt https://plundervolt.com/
- CLKSCREW: Exposing the Perils of Security-Oblivious Energy Management https://www.usenix.org/system/files/conference/usenixsecurity17/sec17-tang.pdf
- Flipping Bits in Memory Without Accessing Them: An Experimental Study of DRAM Disturbance Errors https://users.ece.cmu.edu/~yoonguk/papers/kim-isca14.pdf
- Exploiting the DRAM rowhammer bug to gain kernel privileges https://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
- Security Engineering https://www.cl.cam.ac.uk/~rja14/musicfiles/manuscripts/SEv1.pdf
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