What Is a Supply Chain Attack?
A supply chain attack does not start with your firewall. It starts with someone else’s. Instead of targeting your company directly, a cyber attacker looks for weak spots in your organization’s supply chain. That could be a trusted third-party vendor, a widely used software supplier, or even an outdated package from an open-source code repository. Once they find an opening, they exploit security vulnerabilities to gain access to your systems without ever going through the front door.
The most dangerous part is that it all happens quietly in the background. These attackers compromise a component of the software supply chain well before the final product ever reaches your team. That makes the attack extremely difficult to detect and even more difficult to contain. As businesses rely more on external tools and services, the risk of compromise quickly increases.
Understanding how these attacks happen and learning how to prevent them is essential for protecting your cybersecurity posture and ensuring your systems stay secure.
Understanding the Nature of Supply Chain Attacks
A supply chain attack involves a malicious actor intentionally compromising a component of a product or service before it reaches its intended user. These can range from injecting malicious code during software development to embedding a backdoor in a software update or altering a legitimate repository that distributes third-party software.
The more integrated and fast-moving an organization’s supply chain becomes, the more opportunities there are for attackers to exploit hidden gaps. As businesses expand their digital ecosystems, tracking the full extent of their cybersecurity infrastructure—including inherited dependencies and cloud services—becomes increasingly complex. Failing to address those hidden links can leave critical systems exposed.
Because these attacks typically come from within trusted sources, such as software vendors or suppliers, they can be especially hard to detect. The attacker may exploit a vulnerability in the operating system, the network security layer, or even the source code itself.
Types of Supply Chain Attacks
Supply chain cyber attacks can take many forms. Common types include:
- Software supply chain attacks: Targeting tools, libraries, or plugins used in software development, such as dependency injections or compromised open source components.
- Hardware supply chain attacks: Altering physical components to include surveillance or malware.
- Service provider attacks: Compromising third-party service providers to infiltrate the primary organization.
- Open-source software dependency attacks: Many organizations rely on open-source software to accelerate development. However, attackers can insert malicious code into software libraries or maintainers’ updates. Because these components are trusted and widely reused, a single compromised software module can scale across thousands of applications undetected.
Each of these attack types represents a serious supply chain risk, especially in industries dealing with sensitive information, such as government agencies, finance, and healthcare.
Examples of Supply Chain Attacks
Let’s look at three major supply chain attack examples that have had widespread impact across industries. These examples highlight the evolving tactics of threat actors and the urgent need for stronger supply chain security.
SolarWinds Orion Breach (2020)
The SolarWinds attack remains one of the most well-known and damaging software supply chain attacks to date. A malicious actor successfully injected malicious code (the SUNBURST backdoor) into a SolarWinds’ Orion platform software update.
Over 18,000 customers, including major corporations and government agencies, downloaded the compromised version, unknowingly allowing the attacker to gain access to their systems. This attack exploited trust in a third-party software provider and demonstrated how supply chain risks can create systemic cyber threats.
MOVEit Transfer Vulnerability Exploitation (2023)
In this example, attackers exploited a zero-day vulnerability in MOVEit Transfer, a widely used third-party file transfer tool. The attack enabled threat actors to infiltrate systems and steal sensitive information from hundreds of organizations across sectors. The vulnerability had far-reaching consequences because MOVEit was deeply embedded in many organizations’ workflows.
This was a classic case of a software supply chain attack, where exploiting a single software vendor’s product led to a cascade of data breaches across its user base.
Codecov Bash Uploader Breach (2021)
Threat actors modified Codecov’s Bash Uploader script, which developers use to report code coverage. The altered script was distributed via an official repository, allowing the attackers access to credentials, tokens, and source code in customer CI/CD environments.
This attack was especially dangerous because it compromised the software development pipeline itself, allowing widespread unauthorized access to critical systems. It’s a stark reminder that even development tools and telemetry can become vectors for supply chain cyber-attacks.
How Supply Chain Attacks Work
Here’s how a typical software supply chain attack might unfold:
- A threat actor finds a vulnerability in a dependency used in a popular library.
- They inject malicious code into the component and push it to a public repository.
- Developers unknowingly incorporate the compromised component during software development.
- The final product reaches end-users, spreading the malware or backdoors to multiple systems. Proactive code reviews and supply chain transparency can help mitigate the spread before it reaches production environments.
- The attacker uses the exploit to gain access and infect systems, leading to data breaches or larger security incidents.
Once access is established, attackers often exfiltrate sensitive data or escalate privileges to reach more critical parts of the network. These breaches can severely undermine an organization’s security posture and disrupt operations.
Why Supply Chain Attacks Are Still Rising
The nature of supply chain attacks makes them scalable and stealthy. They’re appealing to attackers because they can impact thousands of organizations with a single breach. The attack surface continues to expand as businesses continue to rely heavily on third-party software, cloud providers, and open-source tools.
Very often, a targeted attack doesn’t begin with the primary victim but with an upstream vendor or developer repository. These initial points of entry are used as stepping stones to move laterally and ultimately compromise software that will be trusted downstream.
Supply chain attacks are still underreported and often discovered only after considerable damage is done. This lack of visibility is a major contributor to their success.
How to Prevent Supply Chain Attacks
To detect a supply chain attack, companies must monitor not just their internal systems but also external integrations and software vendors. Collaboration with security researchers, regular code audits, and automated threat detection tools are essential. Below are actionable steps organizations can implement to reduce their exposure:
Enforce Rigorous Vendor Risk Management
Start with a robust vendor risk assessment framework. Regardless of size, all third-party vendors should be evaluated for cybersecurity maturity before onboarding and continuously monitored afterward. This includes:
- Reviewing security certifications (e.g., ISO 27001, SOC 2). However, don’t assume compliance equals security, but rather ask for proof of ongoing controls testing and evidence of remediation.
- Requiring software bills of materials (SBOMs) to ensure transparency in dependencies. The SBOM should be machine-readable and updated with every release to ensure traceability in the event of a vulnerability disclosure.
- Mandating secure software development lifecycle (SDLC) practices. Focus on vendors who integrate threat modeling and secure coding standards early in development, not just post-build scanning.
- Monitoring fourth-party relationships (your vendors’ vendors). Gaining visibility into your extended ecosystem can uncover hidden dependencies that may not surface during initial procurement.
Ultimately, vendor due diligence should evolve into an ongoing partnership where transparency, threat intelligence sharing, and accountability are baked into the relationship lifecycle.
Implement Continuous Monitoring and Threat Intelligence
Rather than relying on point-in-time audits, organizations need real-time visibility into their entire digital ecosystem. Continuous cyber risk ratings and attack surface monitoring tools can help detect vendor posture shifts or compromise indicators.
Look for tools that offer:
- Alerts for Common Vulnerabilities and Exposures (CVEs) and Exploits in Third-Party Software. Aim for platforms that correlate CVEs with your specific tech stack to prioritize what actually affects your environment.
- Correlated telemetry from dark web chatter, malware networks, and code repositories. Signals from hacker forums or breached credentials can be early indicators before technical vulnerabilities are weaponized.
- Scoring mechanisms that prioritize the most critical risks. Risk scoring should account for exploitability, business impact, and vendor concentration—not just the presence of a vulnerability.
Integrating these insights into your security operations center (SOC) and procurement workflows ensures that intelligence leads directly to timely, risk-informed decisions.
Adopt Zero Trust Principles Across Integrations
Trust, but verify is no longer enough. Apply Zero Trust architecture to your integrations and third-party access:
- Authenticate and authorize every request, no matter where it originates. Use strong identity verification methods, like certificate-based authentication, especially for machine-to-machine communication.
- Enforce least-privilege access for vendors, APIs, and service accounts. Regularly rotate secrets and review entitlements, particularly for legacy systems that vendors may still access by default.
- Monitor API activity and flag anomalies in system-to-system communications. Anomalies like unexpected request volume, new data types, or geolocation shifts can indicate compromised integrations or misuse.
Treat every integration point as a potential breach vector and design your access controls with the assumption that compromise is not a question of if but when.
Secure the Development Pipeline (DevSecOps)
Many supply chain attacks target CI/CD pipelines. Integrate security into each stage of the development lifecycle:
- Scan for vulnerabilities in all dependencies using SCA (Software Composition Analysis) tools.
- Automate code reviews and secrets detection.
- Use tamper-evident logs and signed artifacts for traceability.
Open-source packages should be pinned to trusted versions, and dependencies regularly reviewed for deprecation or known exploits.
Run Incident Response Drills for Vendor Breach Scenarios
Most organizations drill internal incidents like ransomware, but few simulate vendor-origin breaches. Create tabletop exercises that simulate:
- A compromised software update.
- An exposed API token in a third-party tool.
- A malicious insider at a supplier organization.
This prepares teams for coordinated response efforts, including legal, procurement, engineering, and comms.
You can download our Supply Chain Incident Response Playbook to get started.
Collaborate with Security Researchers and the Community
Encourage responsible disclosure and bug bounty participation for your systems and critical vendors and open-source components in your stack. Sharing threat intelligence across industries strengthens collective defenses.
SecurityScorecard participates in multiple threat-sharing initiatives and helps customers evaluate open-source risk at scale.
Protecting Your Digital Ecosystem
The rising tide of supply chain attacks is a call to action for security leaders across industries. Protecting your organization from these threats requires a comprehensive strategy—combining technical defenses, vendor oversight, and policy enforcement.
Companies must treat supply chain security not as an optional layer but as a central pillar of their cybersecurity infrastructure. From open-source software repositories to global vendor ecosystems, every component of an organization’s supply chain must be considered a potential attack vector.
SecurityScorecard provides the tools and intelligence needed to reduce this risk. With capabilities like Supply Chain Risk Intelligence, Automatic Vendor Detection, and MAX Managed Services, you gain real-time visibility into third- and fourth-party security risks, track remediation progress, and prevent malicious code into software before it reaches your production environment.
Our Cyber Risk Ratings and Attack Surface Intelligence modules also help teams monitor their entire digital ecosystem and continuously improve their security posture. Whether you’re managing vendor compliance, overseeing third-party risk management, or assessing security risks in open-source software, SecurityScorecard enables smarter, faster decision-making.
