Introduction
Modern software is no longer built from scratch. Instead, developers assemble applications using open-source libraries, third-party services, cloud platforms, and automated update mechanisms. This approach speeds up innovation and reduces cost. However, it also introduces a dangerous assumption: trust in the form of Supply Chain Attacks.
Supply chain attacks exploit that assumption. Rather than attacking a company directly, attackers compromise something the company already trusts. This could be a software dependency, a build tool, or even a routine update. Once that trusted component is poisoned, the attacker gains access to every system that relies on it.
In recent years, supply chain attacks have shifted from rare incidents to a preferred strategy for advanced attackers. The reason is simple. These attacks scale well, remain stealthy, and bypass traditional security controls.
This blog explains what supply chain attacks are, how they work, and why compromised dependencies and updates pose such a serious risk today.
What Are Supply Chain Attacks?
Supply chain attacks occur when attackers compromise a trusted third-party component to gain indirect access to target systems.
Let’s define the key terms clearly:
- Supply chain refers to all external components used to build and run software
- Dependency is third-party code included in an application
- Trusted update is software delivered through an official update mechanism
Instead of breaking into a system directly, attackers tamper with these components. When organisations install or update them, they unknowingly introduce malicious code into their environment.
This makes supply chain attacks especially dangerous. They exploit trust rather than technical vulnerabilities.
For clarity, supply chain attacks differ from traditional breaches because the malicious code arrives through legitimate channels.
According to CISA, supply chain compromises represent one of the most serious and difficult-to-detect cyber threats today. Read more about it here : CISA Supply Chain Security .
How Supply Chain Attacks Work
Although supply chain attacks vary in technique, most follow a similar pattern.
Step 1: Identify a trusted component
Attackers look for software that:
- Is widely used
- Receives regular updates
- Has access to sensitive systems
Common targets include libraries, build tools, CI/CD pipelines, and update servers.
Step 2: Compromise the source
Once identified, attackers compromise the source by:
- Hijacking developer accounts
- Exploiting weak access controls
- Injecting malicious code into repositories
- Breaching update infrastructure
At this stage, the attack remains invisible to end users.
Step 3: Distribute the malicious update
The compromised component is distributed normally. Because the update appears legitimate, organisations install it without suspicion.
Step 4: Execute malicious payload
After installation, the malicious code executes quietly. It may:
- Create backdoors
- Steal credentials
- Exfiltrate data
- Establish command-and-control access
Step 5: Expand impact
Because many organisations use the same dependency, the attacker gains access to multiple targets simultaneously.
This scalability makes supply chain attacks extremely attractive.
Why Compromised Dependencies Are So Dangerous
Dependencies form the foundation of modern software development. Unfortunately, they also create blind spots.
Implicit trust
Developers trust dependencies because they save time and effort. As a result, dependency updates often receive minimal scrutiny.
Transitive dependencies
Applications rarely depend on just one library. Instead, each dependency pulls in others. This complexity hides risk deep within the codebase.
Limited visibility
Many organisations do not maintain a full inventory of their dependencies. Consequently, they cannot assess exposure accurately.
Update automation
Automatic updates increase speed but reduce control. When a compromised update is released, it spreads rapidly.
Shared exposure
A single compromised library can affect thousands of organisations at once.
Why Trusted Updates Become Attack Vectors
Software updates exist to improve security. Ironically, attackers now use them as delivery mechanisms.
Updates bypass security controls
Firewalls, antivirus tools, and endpoint protections often allow updates by default.
Updates carry high privileges
Update processes frequently run with elevated permissions. This allows malicious code to operate deeply within systems.
Users expect updates
Because updates are routine, they rarely trigger suspicion.
Delayed detection
Malicious updates often remain undetected for months, especially when attackers act quietly.
Real-World Example
Consider a widely used network management tool trusted by enterprises and government agencies. Attackers compromise its build process and inject malicious code into a legitimate update.
Organisations install the update as usual. Soon after, attackers gain backdoor access to internal networks, email systems, and cloud environments.
Because the intrusion originated from a trusted update, security teams initially struggle to identify the cause. By the time detection occurs, attackers have already expanded their access.
This type of incident demonstrates how a single supply chain compromise can cascade across industries and borders.
Why Supply Chain Attacks Are Hard to Detect
Supply chain attacks often evade detection because they blend into normal operations.
Legitimate signatures
Malicious updates may be digitally signed, appearing authentic.
Normal behaviour patterns
The software behaves as expected most of the time, hiding malicious activity.
Delayed payload activation
Attackers often delay execution to avoid suspicion.
Complex investigation paths
Tracing malicious behaviour back to a dependency requires deep analysis.
Lack of monitoring
Many organisations focus monitoring on external threats, not internal trusted components.
Impact on Businesses / Individuals
For Businesses
- Large-scale data breaches
- Intellectual property theft
- Long-term espionage risks
- Regulatory and compliance violations
- Severe reputational damage
- Loss of customer trust
- Costly incident response efforts
For Individuals
- Exposure of personal data
- Identity theft risks
- Loss of confidence in digital services
- Privacy violations
- Secondary fraud and scams
How Organisations Can Reduce Supply Chain Risk
Reducing supply chain risk requires both technical and organisational changes.
Maintain a software inventory
Track all dependencies and third-party components in use.
Verify dependency integrity
Validate sources, signatures, and update authenticity.
Limit update privileges
Reduce the permissions granted to update processes.
Monitor internal behaviour
Detect unusual activity originating from trusted software.
Secure development pipelines
Protect CI/CD systems and developer accounts.
Review third-party risk
Assess vendor security practices regularly.
Apply least privilege
Limit what dependencies can access within the system.
Educate development teams
Awareness reduces risky dependency practices.
Why Supply Chain Attacks Will Continue to Grow
As software ecosystems grow more complex, supply chain risk increases naturally. Attackers follow efficiency. Therefore, compromising one trusted component instead of many targets makes strategic sense.
Additionally, global reliance on open-source software increases exposure. Without stronger governance and monitoring, supply chain attacks will remain a preferred method for sophisticated threat actors.
Conclusion
Supply chain attacks represent a fundamental shift in cyber threats. Instead of attacking systems directly, attackers poison the trust organisations place in dependencies and updates. This approach bypasses traditional defences and scales efficiently.
Understanding how compromised dependencies and trusted updates break security assumptions is essential for modern defence strategies. By improving visibility, reducing implicit trust, and strengthening monitoring, organisations can significantly reduce their exposure.
At eSHIELD IT Services, we help organisations assess supply chain risk, secure development pipelines, and build resilient security architectures that account for modern threats.
Ultimately, protecting trusted systems means questioning trust itself.
FAQ
What is a supply chain attack?
It’s an attack where a trusted third-party component is compromised.
Why are supply chain attacks dangerous?
They exploit trust and affect many organisations at once.
Are open-source projects risky?
They can be if governance and monitoring are weak.
Can antivirus detect supply chain attacks?
Often no, because the software appears legitimate.
Do supply chain attacks affect small businesses?
Yes. Any organisation using third-party software is at risk.
Are software updates always safe?
Usually, but compromised update mechanisms create risk.
How can companies monitor dependencies?
By maintaining inventories and analysing behaviour.
Are supply chain attacks increasing?
Yes, due to software complexity and automation.
Can Zero Trust help with supply chain security?
Yes, by limiting implicit trust within systems.
Who should manage supply chain security?
Security, development, and leadership teams together.
