Pre-silicon / post-silicon: Test access to shared systems resources (memory ranges, control registers, etc.) from untrusted software to verify that the assets are not incorrectly exposed to untrusted agents. Note that access to shared resources can be dynamically allowed or revoked based on system flows. Security testing should cover such dynamic shared resource allocation and access control modification flows.
CWE-1189 Base Stable
Improper Isolation of Shared Resources on System-on-a-Chip (SoC)
This vulnerability occurs when a System-on-a-Chip (SoC) fails to properly separate shared hardware resources between secure (trusted) and non-secure (untrusted) components.
Definition
What is CWE-1189?
This vulnerability occurs when a System-on-a-Chip (SoC) fails to properly separate shared hardware resources between secure (trusted) and non-secure (untrusted) components.
Modern SoCs pack many features but have a limited number of physical connections (pins). To overcome this, they use a technique called pin multiplexing, where a single pin can be configured for different functions at different times. Similarly, internal resources like memory buses or hardware accelerators are often shared across the chip. When these shared resources aren't rigorously isolated, an untrusted agent (like a low-privilege app or peripheral) can potentially access or interfere with resources reserved for trusted system functions, leading to data leaks or system compromise.
For developers, this means security cannot rely solely on software boundaries; hardware-level isolation mechanisms must be correctly configured and audited. Managing these low-level configurations at scale across an entire product fleet is challenging. An ASPM platform like Plexicus can help by detecting such insecure hardware/software interactions and providing prioritized, actionable insights for remediation across your entire application stack.
Real-world impact
Real-world CVEs caused by CWE-1189
-
Processor has improper isolation of shared resources allowing for information disclosure.
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Baseboard Management Controller (BMC) device implements Advanced High-performance Bus (AHB) bridges that do not require authentication for arbitrary read and write access to the BMC's physical address space from the host, and possibly the network [REF-1138].
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable pseudo
MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} 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-1189
- Architecture and Design When sharing resources, avoid mixing agents of varying trust levels. Untrusted agents should not share resources with trusted agents.
Detection signals
How to detect CWE-1189
CWE-1189
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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-1189?
How serious is CWE-1189?
What languages or platforms are affected by CWE-1189?
How can I prevent CWE-1189?
How does Plexicus detect and fix CWE-1189?
Where can I learn more about CWE-1189?
Frequently asked questions
What is CWE-1189?
This vulnerability occurs when a System-on-a-Chip (SoC) fails to properly separate shared hardware resources between secure (trusted) and non-secure (untrusted) components.
How serious is CWE-1189?
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-1189?
MITRE lists the following affected platforms: System on Chip.
How can I prevent CWE-1189?
When sharing resources, avoid mixing agents of varying trust levels. Untrusted agents should not share resources with trusted agents.
How does Plexicus detect and fix CWE-1189?
Plexicus's SAST engine matches the data-flow signature for CWE-1189 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-1189?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/1189.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-1189
CWE-653 Parent
Improper Isolation or Compartmentalization
This vulnerability occurs when an application fails to enforce strong boundaries between components that operate at different security…
CWE-1331 Sibling
Improper Isolation of Shared Resources in Network On Chip (NoC)
This vulnerability occurs when a Network on Chip (NoC) fails to properly separate its internal, shared resources—like buffers, switches,…
CWE-1303 Child
Non-Transparent Sharing of Microarchitectural Resources
This vulnerability occurs when a processor's internal performance features, like caches and branch predictors, are unintentionally shared…
Resources
Further reading
- MITRE — official CWE-1189 https://cwe.mitre.org/data/definitions/1189.html
- Ghost in the PLC Designing an Undetectable Programmable Logic Controller Rootkit via Pin Control Attack https://www.blackhat.com/docs/eu-16/materials/eu-16-Abbasi-Ghost-In-The-PLC-Designing-An-Undetectable-Programmable-Logic-Controller-Rootkit-wp.pdf
- CVE-2019-6260: Gaining control of BMC from the host processor https://www.flamingspork.com/blog/2019/01/23/cve-2019-6260:-gaining-control-of-bmc-from-the-host-processor/
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