Hardware and Firmware Vulnerabilities
Security weaknesses in physical devices and low-level software including firmware vulnerabilities, end-of-life hardware risks, legacy system issues, and hardware-based attacks. These vulnerabilities operate below the OS level.
Understanding Hardware and Firmware Vulnerabilities
Hardware and firmware vulnerabilities exist at the lowest levels of computing systems—below the operating system. These vulnerabilities are particularly dangerous because they're difficult to detect, persist across OS reinstalls, and can undermine all higher-level security controls.
Key vulnerability categories: • Firmware vulnerabilities — Flaws in BIOS/UEFI and device firmware • Hardware vulnerabilities — Physical chip and component flaws • End-of-life systems — Hardware no longer receiving updates • Legacy systems — Older technology with inherent limitations
Attacks at this level are typically sophisticated, often associated with nation-state actors.
Why This Matters for the Exam
Hardware and firmware vulnerabilities are increasingly important in SY0-701 as attackers target lower levels of the stack. Understanding these risks helps with security architecture and procurement decisions.
The exam tests knowledge of firmware security features (Secure Boot, TPM) and the risks of unsupported hardware. Questions may also cover famous hardware vulnerabilities like Spectre/Meltdown.
These vulnerabilities highlight that security extends beyond software—physical devices and their firmware are also attack surfaces.
Deep Dive
Firmware Vulnerabilities
Firmware is software embedded in hardware devices—BIOS/UEFI, device controllers, IoT devices.
Why Firmware Is Targeted:
- •Executes before OS loads
- •Often not scanned by security tools
- •Persists through OS reinstallation
- •High privileges when running
- •Less scrutiny than OS code
BIOS/UEFI Vulnerabilities:
| Type | Description |
|---|---|
| Bootkit | Malware in boot process |
| UEFI rootkit | Persists in firmware |
| Secure Boot bypass | Disables boot security |
| Firmware backdoor | Implanted access |
Device Firmware Risks:
- •Network cards (NIC firmware)
- •Storage controllers (SSD, HDD firmware)
- •Management interfaces (IPMI, iLO, DRAC)
- •USB devices (BadUSB attacks)
- •IoT devices (cameras, sensors)
Firmware Attack Example - BadUSB:
- •USB device firmware reprogrammed
- •Device appears as keyboard
- •Types malicious commands when connected
- •No file to scan—attack is in firmware
Firmware Security Controls:
- •Secure Boot (verify boot components)
- •Firmware signing and verification
- •TPM (Trusted Platform Module)
- •Regular firmware updates
- •Firmware integrity monitoring
Hardware Vulnerabilities
Physical flaws in processors, chips, and components.
CPU Vulnerabilities:
Spectre/Meltdown (2018)
- •Exploit CPU speculative execution
- •Read protected memory
- •Affects virtually all modern processors
- •Requires OS and firmware patches
Other CPU Vulnerabilities:
- •Foreshadow (Intel SGX attack)
- •Rowhammer (memory bit flipping)
- •Side-channel attacks (timing, power analysis)
Hardware Attack Types:
| Attack | Description |
|---|---|
| Side-channel | Infer data from timing/power/radiation |
| Cold boot | Extract RAM contents after power-off |
| JTAG/debug ports | Access debug interfaces |
| Hardware implants | Physical backdoor devices |
| Bus sniffing | Intercept hardware communications |
Hardware Security:
- •Tamper-evident cases
- •Disable debug ports
- •Encrypted memory (AMD SEV, Intel TME)
- •Physical security controls
- •Supply chain verification
End-of-Life (EOL) Hardware
Hardware no longer supported by manufacturers.
EOL Risks:
- •No firmware updates
- •No security patches
- •Driver support ends
- •Known vulnerabilities remain
- •Compliance issues
EOL Examples:
- •Older network equipment
- •Legacy servers
- •End-of-support storage systems
- •Discontinued IoT devices
Managing EOL Hardware:
- •Track hardware lifecycle
- •Plan replacements before EOL
- •Isolate if replacement delayed
- •Enhanced monitoring
- •Document risk acceptance
Legacy Systems
Older technology with inherent security limitations.
Legacy Hardware Issues:
- •Lacks modern security features
- •No TPM or Secure Boot
- •Weak encryption support
- •Incompatible with current software
- •Physical security limitations
Legacy Mitigation:
- •Network segmentation
- •Compensating controls
- •Enhanced monitoring
- •Migration planning
- •Risk acceptance documentation
Comparison: Hardware vs. Firmware vs. Software
| Layer | Persistence | Detection | Patching |
|---|---|---|---|
| Hardware | Permanent | Very difficult | Replacement |
| Firmware | High (survives reformat) | Difficult | Firmware update |
| OS | Medium | Moderate | OS update |
| Application | Low | Easy | App update |
How CompTIA Tests This
Example Analysis
Scenario: Security researchers discover that a company's servers have management interfaces (IPMI) with factory default credentials exposed to the network. An attacker uses these credentials to access the IPMI, modify the server's UEFI firmware, and install a persistent rootkit.
Analysis - Firmware-Level Compromise:
Attack Chain: 1. Discover IPMI exposed with default credentials 2. Access out-of-band management interface 3. Modify UEFI firmware from management interface 4. Install firmware-level rootkit 5. Rootkit persists through OS reinstallation
Why This Is Severe: • Below OS level — Operating system can't detect it • Persistent — Survives disk wiping and OS reinstall • Full control — Can manipulate anything above it • Difficult to remove — Requires firmware reflashing
Defense Layers Bypassed: • Antivirus (can't scan firmware) • EDR (operates at OS level) • OS hardening (doesn't protect firmware) • Full disk encryption (firmware loads before)
Proper Defenses: • Change default IPMI credentials immediately • Restrict management interfaces to dedicated network • Enable Secure Boot to detect firmware changes • Use TPM for firmware integrity verification • Firmware signing and verification
Key insight: Management interfaces are often overlooked but provide powerful access below the OS level.
Key Terms to Know
Common Mistakes to Avoid
Exam Tips
Memory Trick
"FELS" - Hardware/Firmware Vulnerabilities
- •Firmware vulnerabilities (BIOS, UEFI, device firmware)
- •End-of-life hardware (no more support)
- •Legacy systems (old, limited security)
- •Side-channel attacks (hardware-level inference)
Persistence Level (Most to Least): Hardware → Firmware → OS → Application "Hardware First, Applications Last"
Firmware Attack Memory: Firmware = Below OS = Survives Beyond reinstall
- •Management Interface Risks: "IPMI"
- •Insecure defaults
- •Powerful access
- •Modify firmware
- •Invisible to OS
Test Your Knowledge
Q1.An attacker modifies a server's UEFI firmware to include malicious code. What characteristic makes this attack particularly concerning?
Q2.What security feature verifies that boot components have not been tampered with before loading the operating system?
Q3.A company uses servers that reached end-of-life and no longer receive firmware updates. What is the PRIMARY security concern?
Want more practice with instant AI feedback?
Practice with AIContinue Learning
Ready to test your knowledge?
Practice questions on hardware and firmware vulnerabilities and other Objective 2.3 concepts.