from: https://www.perplexity.ai/search/12a5cb01-578c-4f70-942b-5a3d992b5654
biggest missing thing: mention of things from this community, such as
that wiki containing endless photographs of discovered implants

prompt: Look for popular and recent research, news, and discussions
regarding pcb trojans and malicious counterfeits snuck into devices by
3rd parties in the supply chain. Write up some text, the first part
regarding the threat of pcb trojans and occurrences where they have
been found or suspected, and in the second part relate how people of
different skill levels (ranging from layperson to expert researcher or
hacker) can mitigate them. Including also information on political,
policy, etc changes that could mitigate or worsen the situation. Keep
each item brief, such that it’s somewhat like a couple lists of cited
factoids, with engaging pacing.

assistant: # PCB Trojans and Malicious Counterfeits: Threats,
Occurrences, and Mitigation

## The Threat: Hardware Implants in Circuit Boards

**Suspected Supply Chain Intrusions**

The most widely discussed incident involves claims that Chinese
operatives inserted rice grain-sized spy chips onto Supermicro server
motherboards during manufacturing, allegedly affecting nearly 30
companies including Amazon and Apple. While Supermicro, Apple, and
Amazon vehemently denied these allegations and third-party
investigations found no evidence, the story highlighted a plausible
attack vector that security experts acknowledge is technically
feasible. The U.S. Department of Defense reportedly discovered
thousands of its computers sending military network data to China due
to hidden code in chips, according to the same
reporting.[1][2][3][4][5]

**Manufacturing-Stage Vulnerabilities**

Untrusted foundries present significant risks, as malicious actors can
embed tiny, undetectable circuits during fabrication. Modern PCBs
feature highly integrated designs with multiple layers, hidden vias,
and embedded passive components—complexity that provides ample hiding
opportunities for adversaries. Filler cells can be substituted with
logic gates inducing denial of service, or fuses can be disabled to
create backdoors. Counterfeit components further compound the threat,
as substandard or malicious parts may host malware, firmware exploits,
or hardware Trojans that prove fatal in field deployment.[6][7][1]

**Real-World Impact Examples**

Suspect counterfeit parts have been found in military equipment
including SH-60B helicopter infrared systems, memory chips in USAF
C-130J and C-27J cargo planes, and ice detection modules on Navy P-8A
Poseidon aircraft—all traced to Chinese manufacturing plants. In
Syria, a radar system allegedly failed due to a backdoor built into
hardware, demonstrating how Trojans can disable critical defenses. The
2007 Syrian radar incident remains a classic example of hardware
tampering enabling physical attacks.[8][1]

## Mitigation Strategies by Skill Level

### For Laypersons and Hobbyists

**Visual Inspection and Documentation**
Carefully examine PCBs for unexpected components, inconsistent
soldering quality, or boards that appear different from reference
designs. Photograph boards upon receipt to document their original
state. While modern Trojans can be microscopic, some counterfeits and
tampered units show visible anomalies like incorrect component
markings or poor workmanship.[6]

**Firmware Vigilance**
Regularly update firmware from official manufacturer sources only.
Attackers with physical access can modify components, making
post-purchase updates crucial for addressing known exploits. Enable
automatic security updates where available and verify cryptographic
signatures when manually installing firmware.[6]

**Trusted Sourcing**
Purchase from authorized distributors or directly from manufacturers
rather than third-party marketplaces. The risk of counterfeit
components increases dramatically when sourcing from untrusted
suppliers, as recycled or remarked parts may contain hidden
modifications.[1][6]

### For Intermediate Technicians and Engineers

**JTAG Boundary Scan Testing**
Utilize JTAG boundary scan to verify component presence and
connectivity without physical probing. This method detects component
misplacement by comparing golden and test PCBs, though it requires a
known-good reference board. Automated optical inspection systems can
also identify text and component placement discrepancies.[9][10]

**Power Side-Channel Monitoring**
Implement differential power analysis to detect Trojans by observing
fluctuations in power consumption on the PCB's power distribution
network. A purpose-built prototype demonstrated detection of alien
components without interfering with main functionality. For
I/O-powered Trojans, monitor power consumption patterns from
legitimate chip I/O ports using machine learning
classifiers.[10][11][12]

**Supply Chain Verification**
Request supply chain documentation and component traceability from
manufacturers. Conduct functional testing under varied conditions to
verify behavior against expected outcomes. For critical applications,
consider X-ray imaging to reveal hidden circuits or anomalies within
multi-layer boards.[6]

### For Expert Researchers and Hardware Hackers

**Machine Learning-Based Detection**
Deploy One-Class Support Vector Machines or Local Outlier Factor
algorithms trained on power consumption patterns to detect stealthy
Trojans in real-time. Experimental results show F1-scores above 99.7%
for detecting 50mW Trojans, with models validated in hard silicon.
This approach enables runtime monitoring without golden
models.[13][10]

**Multi-Modal Side-Channel Analysis**
Combine electromagnetic fingerprinting, thermal imaging, and path
delay analysis to create comprehensive Trojan signatures. Magnetic
side-channel spectrum models can assess detectability of various
hardware Trojans, with electromagnetic fingerprints proving effective
for identification. This method works even when Trojans alter existing
silicon slightly rather than adding obvious components.[3][14][9]

**Reverse Engineering and Formal Verification**
Employ automated reverse engineering tools to extract netlists and
compare against golden designs. For IP cores, use static formal
verification methods like Formal-PCH, VIPR, and TRIT-PCB to detect
malicious inclusions. Break Trojan activation sequences by scrambling
inputs supplied to third-party IP blocks.[7][15]

## Political and Policy Developments

**Strengthening Measures**

The January 2025 Cybersecurity Executive Order mandates that federal
agencies only acquire software from providers demonstrating secure
development practices, requiring machine-readable attestations and
artifacts. The Cyber Trust Mark program, reinforced by NIST SP
800-213, will exclude devices lacking security certification from
federal procurement entirely. This creates powerful competitive
incentives for early compliance.[16][17]

The Department of Defense's latest strategy makes CMMC 2.0 Level 2
assessments mandatory by end of FY25, with AI-driven Software Fast
Track (SWFT) processes for rapid risk assessment. A July 2025 DoD
directive explicitly states the Department "will not procure any
hardware or software susceptible to adversarial foreign influence,"
urging adherence to CMMC, SWFT, and Secure Software Development
Framework standards.[18][19]

The EU Cyber Resilience Act requires mandatory SBOMs (Software Bills
of Materials) for all products containing software or firmware,
enforcing secure-by-design principles from development through
lifecycle support.[20]

**Potential Risks and Loopholes**

Global supply chain complexity continues to challenge enforcement,
with about 75% of mobile phones and 90% of PCs manufactured in China,
giving adversaries inherent access opportunities. Policy
implementation timelines extending into 2026 create windows of
vulnerability. The reliance on third-party attestations rather than
direct hardware testing may allow sophisticated Trojans to evade
detection, particularly if compromises occur at the CAD tool level
before design completion.[17][1]

**Emerging Concerns**

The shift toward continuous validation and AI-driven anomaly detection
introduces new attack surfaces—adversaries could potentially poison
training data or exploit ML model vulnerabilities. As detection
methods improve, Trojans are becoming stealthier, consuming less power
and triggering only under specific conditions, making even advanced
detection increasingly challenging.[11][10][13]

Sources
[1] Threats to ICT supply chains including Counterfeit electronic ...
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[2] Hardware Trojans and Supply Lines | Proceedings
https://www.usni.org/magazines/proceedings/2021/april/hardware-trojans-and-supply-lines
[3] Supermicro spy chips, the sequel: It really, really happened ...
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[4] Super Micro Issues Strongest Denial yet to Bloomberg ...
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[5] Years later, Bloomberg doubles down on disputed Supermicro supply
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[6] How Secure Are Printed Circuit Boards Against Trojan Attacks?
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[8] Hardware Trojans in Chips: A Survey for Detection and Prevention
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[9] The Most Significant Cyberattack in History Prompts Questions ...
https://www.allaboutcircuits.com/news/most-significant-cyberattack-in-history-prompts-questions-supply-chain-security/
[10] PCB Hardware Trojan Run-Time Detection
https://livrepository.liverpool.ac.uk/3166747/6/PCB_Hardware_Trojan_Run-Time_Detection_Through_Machine_Learning.pdf
[11] Investigation into Detection of Hardware Trojans on Printed
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[12] Hardware Trojan Detection on a PCB Through Differential Power ...
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[13] A Board-level Hardware Trojan Detection Method
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[14] [PDF] Detecting Hardware Trojans in PCBs Using Side-Channel
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[15] IP Trojan Attacks - CAD for Assurance
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[17] Building the Cyber Fortress: New Cybersecurity Executive Order
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[18] The DoD's Latest Supply Chain Cybersecurity Strategy - DLT
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[19] The Rise of SBOM Requirements In Cybersecurity Guidelines and ...
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[20] What EO 14028, EU CRA, and NIST CSF 2.0 Mean for Software ...
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[21] Cybersecurity & the Supply Chain: Safeguarding PCBA Builds
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[22] [PDF] 5G Hardware Supply Chain Security Through Physical
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[24] Detecting Imported Hardware Trojans - Northrop Grumman
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[33] Supermicro Refutes Claims in Bloomberg Article
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[35] China Used a Tiny Chip in a Hack That Infiltrated U.S. Companies
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