The New Invisible Threat: Software Supply Chain Attacks More than Double in 2025
Incidents of software supply chain attacks more than doubled globally in 2025, exposing critical gaps in enterprise preparedness. The attack on tj-actions in March 2025 compromised CI/CD pipelines in thousands of repositories. The XZ Utils case from 2024, where an attacker spent two years building trust before inserting a backdoor, set the standard for the modern threat.
The attack that set the standard for the modern software supply chain threat was not swift. It was patient. For over two years, an unknown actor regularly contributed to XZ Utils, a Linux compression utility found in nearly every distribution of the operating system. He gained the community's trust, obtained maintainer access, and in March 2024, inserted a carefully crafted backdoor into the official versions of the project. The discovery was accidental: a Microsoft engineer noticed anomalous performance behaviour before the malicious code reached production distributions.
The XZ Utils was not the peak. It was the precedent.
The Incidents of 2025
In March 2025, the compromise of tj-actions, a widely used tool in continuous integration pipelines on GitHub, demonstrated that the risk to CI/CD is not theoretical. Secrets were exposed via runtime memory dumping in thousands of repositories that used the tool.
In August 2025, malicious versions of the Nx package included post-installation scripts that swept affected systems for tokens, SSH keys, and API secrets, exfiltrating the data to repositories controlled by the attackers. In September, the TinyColor campaign injected malicious scripts into the popular colour package and dozens of related packages, transforming them into a self-propagating worm that harvested credentials during installation.
Incidents of software supply chain attacks more than doubled globally in 2025, according to security researchers monitoring public and private repositories.
The Structural Difference from Conventional Attacks
In a conventional attack, the adversary attempts to breach the organisation's perimeter. In a supply chain attack, the adversary compromises something the organisation already trusts. The difference is critical: the detection and response controls protecting the perimeter are ineffective against malicious code entering as a legitimate update to a dependency.
SolarWinds demonstrated this in 2020, with 18,000 organisations installing compromised updates. The average cost per affected organisation was $12 million, with the incident remaining undetected for approximately nine months.
What Mature Organisations Are Doing
The response to supply chain risk involves layers of controls that go beyond antivirus and firewall. Software Bill of Materials (SBOM): an inventory of every software component and its provenance, mandated by an executive order for federal government suppliers since 2021 and progressively adopted by large corporations. Package integrity verification: cryptographic checks of hashes before installing dependencies in production environments. Version pinning: avoiding dependencies that automatically update to the latest version, prioritising specific audited versions. Pipeline behaviour monitoring: detecting data exfiltration or access to credentials by build processes that should not have that access.
The risk of supply chain cannot be eliminated. It can be managed with the level of attention that was once reserved solely for the external perimeter.