Learn how supply chain attacks work and how to detect vendor compromises before they reach your systems.
• Supply chain attacks exploit trust between you and your vendors to bypass security controls entirely
• Attackers either poison software you install or breach vendors who hold your data
• Detection requires continuous monitoring since vendors often don’t discover their own breaches for months
• Dark web monitoring catches vendor credential exposures and data leaks before official disclosure
30% of all breaches now involve third parties. That’s double last year’s rate, according to Verizon’s 2025 Data Breach Investigations Report. When attackers compromise your vendors, they get access to your data without ever touching your network.
Supply chain attacks work because attackers target the weakest link. Your security might be solid. But your vendors? They might not have the same budget or security maturity. One compromised vendor becomes a gateway to thousands of downstream victims.
The SolarWinds attack showed how much damage supply chain compromises cause. A single backdoor in a software update reached 18,000 customers including government agencies. But SolarWinds wasn’t unique. These attacks happen constantly.
This guide examines 10 major supply chain attack examples across software and vendor compromises. You’ll see how each supply chain cyber attack worked and learn detection strategies that catch these threats early.
Your vendors have keys to your kingdom. When attackers steal those keys, they walk right in.
A supply chain attack targets the trust between you and your vendors or software providers. Instead of attacking you directly, attackers compromise a third party that already has legitimate access to your systems or data.
Supply chain attacks exploit trust. You trust your software vendors to ship clean updates. You trust your service providers to protect their credentials. Attackers abuse that trust to bypass your security entirely.
Attackers identify vendors with access to multiple targets. A single compromised MSP can reach hundreds of clients. One backdoored software update can infect thousands of customers.
Here’s how it usually works. Attackers first compromise a vendor through phishing or stolen credentials. Then they use that vendor’s legitimate access to reach downstream targets. Because the access comes from a trusted source, security controls often miss it.
Software supply chain attacks inject malicious code into legitimate software. Attackers might compromise build systems or tamper with update mechanisms. When customers install the software, they install the malware too.
Vendor or third-party attacks exploit the access that service providers have to customer environments. Attackers steal vendor credentials or compromise vendor systems to pivot into customer networks.
Both work the same way. They turn trusted relationships into attack vectors.
Software supply chain attacks weaponize the tools you trust. These five attacks show how a single compromise can spread to thousands of victims.
Russian intelligence operatives compromised SolarWinds’ build system and inserted a backdoor called SUNBURST into Orion software updates. Over 18,000 customers downloaded the malicious update between March and June 2020.
The attackers specifically targeted government agencies and major corporations. They moved laterally through victim networks for months before FireEye detected the breach in December 2020. This showed how software supply chains create single points of failure.
For detailed analysis, see our SolarWinds data breach case study.
The 3CX attack was a cascading supply chain compromise. Attackers first breached Trading Technologies, a financial software company. They used that access to compromise 3CX, a VoIP provider with 600,000 business customers.
Attackers inserted malware into 3CX’s legitimate desktop application. When employees installed the update, the malware contacted attacker-controlled servers. Security researchers attributed the attack to North Korean attackers.
The Cl0p ransomware group exploited a zero-day vulnerability in MOVEit Transfer, a widely used file transfer application. They stole data from over 2,700 organizations before Progress Software could patch the vulnerability.
Victims included government agencies and healthcare providers. Attackers didn’t encrypt systems. They simply exfiltrated data and demanded payment to prevent publication. One vulnerable application exposed an entire ecosystem.
REvil ransomware operators exploited vulnerabilities in Kaseya’s VSA remote management software. Because MSPs use Kaseya to manage their clients’ systems, the attack spread to approximately 1,500 downstream businesses.
Attackers pushed ransomware through Kaseya’s legitimate update mechanism. The timing was strategic. They launched on July 2nd when IT staff would be preparing for the holiday weekend. Small businesses bore the brunt because their MSPs couldn’t recover quickly.
Russian military attackers compromised M.E.Doc, accounting software mandatory for businesses operating in Ukraine. They pushed a destructive payload disguised as a software update.
NotPetya spread beyond Ukraine through multinational companies with Ukrainian operations. Maersk and Merck each suffered billions in damages. The total global impact exceeded $10 billion. The attack remains the most destructive cyberattack in history.
Software isn’t the only supply chain risk. Service providers and business partners have access that attackers can exploit. These five recent supply chain attacks show how vendor compromises reach their customers.
ALPHV/BlackCat ransomware operators attacked Change Healthcare, a clearinghouse processing billions of healthcare transactions annually. The attack disrupted claims processing across the US healthcare system for weeks.
Change Healthcare connects pharmacies and healthcare providers. When their systems went down, providers couldn’t verify insurance coverage or process prescriptions. When critical infrastructure vendors go down, everyone feels it.
Attackers compromised CDK Global, which provides dealer management software to approximately 15,000 auto dealerships. The attack forced dealerships to process sales manually, delaying transactions and creating chaos during peak summer buying season.
Some dealers reported losing millions in sales. One vendor took down an entire industry.
Attackers breached Okta through a third-party support contractor. They gained access to Okta’s internal systems and customer data. Because Okta provides identity management for thousands of companies, the breach created downstream risk.
Okta initially downplayed the incident. Later disclosures revealed attackers accessed customer information. Identity providers make attractive targets because one breach reaches thousands of customers.
For more details, see our Okta data breach case study.
Attackers stole credentials from Fazio Mechanical, an HVAC contractor working with Target. They used those credentials to access Target’s network and eventually reach point-of-sale systems.
The breach exposed 40 million payment cards and cost Target over $200 million. Even an HVAC vendor can be the way into a Fortune 500 company.
For complete analysis, see our Target data breach case study.
Similar to Target, attackers compromised a third-party vendor to access Home Depot’s network. They installed malware on self-checkout terminals and stole 56 million payment cards over five months.
The attack went undetected until banks noticed patterns in fraudulent transactions. Home Depot spent $179 million on breach response.
See our Home Depot data breach case study for details.
Supply chain attacks succeed because they exploit the trust that makes business possible.
Third-party risk is the potential for security incidents originating from your vendors or service providers. When third parties have access to your systems or data, their security failures become your security failures.
Your security tools watch for suspicious activity. But vendor access looks legitimate. When an MSP pushes updates to managed systems, that’s normal behavior. When a software vendor ships a new version, you install it.
Attackers exploit this trust to bypass controls. The malicious activity hides inside expected behavior.
Large enterprises invest millions in security. Their smaller vendors might not have the same resources. Attackers know this. They target the vendor with weak email security rather than the enterprise with a mature SOC.
The Target attack illustrates this perfectly. Target had strong security. Their HVAC vendor didn’t. Attackers chose the easier path.
Attacking companies one by one is slow. Attacking a vendor that serves thousands of companies is way faster. SolarWinds reached 18,000 customers through a single compromise. Kaseya’s attackers hit 1,500 businesses in one operation.
Attackers get more victims for the same effort.
Third-party breaches take nearly nine months to detect on average, according to IBM’s Cost of a Data Breach Report. SolarWinds proved this timeline isn’t exaggerated.
Long dwell times mean more data stolen and more systems compromised. Vendors often don’t know they’re breached. And if they don’t know, they can’t tell you.
You can’t control your vendors’ security. But you can watch for signs they’ve been compromised. Early detection limits damage.
When vendor employees’ credentials appear in stealer logs or third-party breaches, that’s an early warning sign. Those credentials might provide access to your systems.
Compromised credential monitoring watches for credentials associated with your critical vendors. You’ll know when vendor accounts are at risk before attackers exploit them.
Criminal marketplaces trade in stolen data and network access. Initial access brokers sell VPN credentials and RDP access to compromised organizations.
When your vendors appear on these marketplaces, assume they’ve been compromised. Dark web monitoring catches these signals while there’s still time to respond.
Ransomware groups announce victims on leak sites before publishing stolen data. If your vendor appears on a leak site, assume your data is exposed.
Monitoring leak sites gives you advance notice. You can also search leaked files for your own data. If you find your company mentioned in a vendor’s breach, you’ll know before anyone notifies you. That gives you time to assess exposure and prepare your response.
Detection works best alongside your broader vendor risk management program. Combine continuous monitoring with periodic assessments.
Questionnaires tell you about vendor controls. Monitoring tells you when those controls fail.
You can’t fully trust any third party. To mitigate supply chain attacks, build defenses assuming your vendors will eventually be compromised.
Zero trust assumes breach. Every access request gets verified regardless of the source. Even if attackers compromise a vendor, they face additional barriers.
Limit vendor access to only what’s necessary. Monitor vendor connections for anomalies. Don’t let vendor credentials provide unlimited access.
SBOMs list the components in software you use. When a vulnerability is discovered in a library, you can quickly identify affected systems.
CISA recommends SBOMs as a supply chain cyber security control. They show you what’s inside your software.
Annual questionnaires miss what happens between assessments. Supplement point-in-time reviews with continuous monitoring.
Watch for vendor credential exposures. Track vendor mentions on criminal forums. Monitor ransomware leak sites. These signals indicate compromise faster than self-reported assessments.
Use code signing to verify software updates come from legitimate sources. Monitor build systems for unauthorized changes. Test updates in isolated environments before deployment.
SolarWinds could have been detected earlier with better integrity monitoring. The malicious code wasn’t in source control. If they’d compared builds to source, they would have caught the tampering.
Supply chain attacks exploit the trust that makes business possible. From SolarWinds to Change Healthcare, these attacks prove that your security depends on your vendors’ security too.
Key takeaways:
Don’t wait for vendors to tell you they’ve been breached. By then, attackers may have already stolen your data.
Want to see what’s exposed? Run a dark web scan to check your organization’s credential exposure right now.
SolarWinds is the most well-known supply chain attack. Russian attackers compromised the Orion software build system in 2020 and distributed malware through legitimate updates. Over 18,000 customers installed the backdoored software, including multiple US government agencies. The attack went undetected for nine months.
Supply chain attacks take an average of 267 days to identify and contain according to IBM’s Cost of a Data Breach Report. SolarWinds went undetected for over nine months. MOVEit was exploited for weeks before discovery. That’s why you can’t rely on vendors to notify you. You need your own dark web monitoring to catch early warning signs.
30% of all breaches had third-party involvement according to the 2025 DBIR. That’s double the previous year’s rate. Resilience Insurance reports 40% of their claims involved third-party compromises. These numbers keep climbing as attackers realize vendors are often easier targets than their customers.
Monitor the dark web for your vendors’ data. When vendor employee credentials appear in stealer logs, that’s an early warning sign. Watch criminal marketplaces for mentions of your vendors. Compromised credential monitoring catches these exposures before attackers exploit them. You’ll know about problems before vendors do.
Manufacturing faces the highest attack volume at 26% of all attacks according to IBM X-Force. They play a critical role in physical supply chains, making them attractive targets. Healthcare and financial services follow closely because they handle valuable data and connect to many vendors.
Software supply chain attacks compromise code or build systems to distribute malware through legitimate updates. SolarWinds and 3CX are examples. Vendor supply chain attacks exploit third-party credentials to reach downstream targets. The Target breach started when attackers stole an HVAC vendor’s credentials. Both exploit trust but use different methods.
Third-party breaches average $4.91 million according to IBM’s 2025 report. That’s the second-highest cost category after malicious insiders. The extended detection time drives up costs. When you don’t know you’re breached for 267 days, attackers have plenty of time to cause damage.
Authentication Dark Web Monitoring Credential Monitoring Security Tools
Top 10 Account Takeover Solutions at a Glance Platform Category Best For Breachsense Credential Intelligence Dark web …
Dark Web Monitoring Compromised Credentials DarkOwl Threat Intelligence Credential Monitoring
What Does DarkOwl Do? DarkOwl is a darknet data platform. They collect content from across the dark web and make it …