GitHub has become the latest front in a supply chain campaign that keeps mutating. The threat actor behind the GhostAction operation—previously known for slipping malicious GitHub Actions workflows into compromised projects—has broadened its playbook, according to research from OpenSourceMalware reported by The Hacker News. The group is now phishing open-source developers and distributing a credential stealer concealed inside what appears to be a font file, with the payload found planted across 94 GitHub repositories.

From workflow injection to social engineering

The original GhostAction attacks relied on workflow injection: by tampering with CI/CD configuration, the actor could execute code inside a victim project's build pipeline and reach the secrets and tokens that pipelines depend on. The new activity suggests the operators are adapting their tradecraft, likely in response to defensive measures and takedowns that have made the earlier approach harder to sustain.

Instead of only hijacking automation, the attackers now appear to target the developers themselves. The phishing lure draws maintainers toward repositories containing a malicious component disguised as a font—a file type that rarely raises suspicion and is often loaded by web applications, documentation sites and build tooling without a second thought.

Why a font is an effective disguise

Font files are attractive cover for several reasons. They are binary, so static review is uncommon; they are frequently bundled into projects as assets; and their presence in a repository is unremarkable. Once a developer or automated process interacts with the malicious file, the embedded stealer can harvest credentials—repository tokens, environment variables, and other secrets that grant access to source code and CI/CD pipelines.

That access is exactly what makes this campaign dangerous. A stolen developer token can let an attacker push commits, alter workflows, or publish packages under a trusted identity, effectively turning a single compromised account into a foothold across every project that developer touches.

The scale: 94 repositories

The discovery of the payload in 94 GitHub repositories points to a deliberate, distributed approach rather than a one-off compromise. Spreading malicious artifacts across many projects increases the odds that at least one victim will interact with them, and it complicates cleanup, since defenders must identify and remediate each affected repository individually.

Open-source ecosystems are especially exposed to this model. Maintainers often juggle multiple projects, accept contributions from strangers, and rely on automation that runs with elevated privileges. Each of those characteristics is a lever an attacker can pull.

Practical guidance for maintainers and security teams

While the full technical details of the campaign are best reviewed in the original research, the incident reinforces several durable lessons:

  • Treat repository assets as code. Review binary additions such as fonts, images and archives in pull requests, and require human approval for changes to build and workflow files.
  • Scope and rotate tokens. Limit the permissions of personal access tokens and CI/CD secrets, prefer short-lived credentials, and rotate anything that may have been exposed.
  • Audit workflow changes. Unexpected modifications to GitHub Actions configuration should trigger review, since workflow files are a direct path to code execution.
  • Watch for social engineering. Phishing aimed at maintainers is often the first step; verify unexpected requests, links and repository invitations out of band.
  • Monitor for anomalous activity. Unfamiliar commits, new collaborators, or unexpected package publications should be investigated promptly.

The bigger picture

GhostAction's evolution illustrates a broader trend in open-source attacks: adversaries are not abandoning automation-based techniques but layering them with human-focused deception. The combination of trusted platforms, low-suspicion file types, and the high value of developer credentials makes for a potent formula.

The 94-repository footprint is a reminder that supply chain security is not only about the code a project ships—it is also about the accounts, tokens and workflows that surround it. Organizations consuming open-source software should extend their scrutiny to the maintainers and pipelines behind their dependencies, not just the dependencies themselves.