Fake Open VSX extensions expose developer environments

A coordinated campaign involving 77 counterfeit extensions on the Open VSX Registry exposed sensitive information about developer machines, Git repositories and continuous integration environments, highlighting a growing software supply-chain risk around code-editor plugins.

The extensions appeared between July 26 and August 1 and impersonated legitimate tools available through the Visual Studio Code ecosystem. All 77 had been removed from Open VSX by August 3, but security specialists have warned that marketplace removal does not eliminate copies already installed on developer workstations, cloud development environments or automated build images.

The packages copied names, namespaces and descriptions associated with genuine extensions while being uploaded by accounts unrelated to the original publishers. Many carried version number 0.0.1 and substituted the legitimate extension logic with code designed primarily to gather and transmit information from the host environment.

Of the 77 packages, 58 collected relatively limited information, principally machine hostnames and, in some cases, workspace folder names and editor versions. The remaining 19 conducted substantially deeper reconnaissance.

Those variants collected operating system usernames and hostnames, machine identifiers, editor names and versions, platform architecture, locale and timezone information. They also captured the name and full filesystem path of the workspace open in the editor.

The packages inspected Git metadata to identify remote hosts and organisations, the domain used in the developer’s configured email address, the current branch and the HEAD commit hash. They could enumerate as many as 60 installed extensions, providing attackers with a detailed picture of the tools present on a developer machine.

Information connected with CI/CD and cloud-development environments was also collected. The affected extensions checked identifiers associated with GitHub, GitLab, Azure DevOps, Buildkite and CircleCI, alongside information from GitHub Codespaces and Gitpod environments.

Such metadata can be highly valuable even without direct credential theft. A combination of repository organisation, private project path, branch information, developer identity indicators and CI platform details can help an attacker map an organisation’s development infrastructure and identify systems for subsequent targeting.

Analysis of the discovered packages found no evidence that they stole source code, passwords, authentication tokens, SSH keys or browser information. The distinction is significant because the campaign appears to have concentrated on reconnaissance rather than immediately harvesting credentials or implanting a more destructive payload.

The operators’ objective remains unclear. However, several technical features suggest deliberate and persistent data collection rather than accidental telemetry. Some extensions repeatedly attempted transmission for as long as seven days if the first connection failed.

All 77 communicated with infrastructure associated with the same domain, mangorbit. com, which was registered on July 15, 11 days before the first counterfeit packages appeared. Individual packages contained tracking identifiers that could allow the operator to determine which impersonated extension had been installed.

Some variants also supported alternative communications channels. Their code could query DNS records for replacement data-exfiltration addresses if the primary infrastructure became unavailable, while retry mechanisms allowed the collection process to resume after the editor restarted.

The campaign has drawn wider attention because Open VSX has become an important distribution channel for extensions used by VS Code-compatible development platforms. The registry passed 300 million monthly downloads this year and supports more than 10,000 extensions from over 6,500 publishers, serving platforms including Cursor, Windsurf, VSCodium, Amazon Kiro, Google Antigravity and other AI-assisted or cloud-based coding environments.

A separate examination during July identified about 150 extension names on Open VSX that could potentially create provenance confusion by matching established extensions while being controlled by unrelated publishers. Those packages were not found to be actively malicious during examination, but the issue demonstrated how differences between marketplace publisher identities can enable convincing impersonation.

Open VSX has been strengthening its safeguards against such activity. Its pre-publication verification framework includes checks for namespace impersonation, extension-name spoofing, embedded credentials, known malicious patterns and suspicious uploads. The Eclipse Foundation has also introduced a security researcher recognition programme to encourage vulnerability reporting and coordinated remediation.

The latest campaign nevertheless shows why organisations are increasingly treating editor extensions as software dependencies rather than harmless productivity add-ons. Development machines frequently have access to private repositories, environment variables, cloud platforms and deployment systems, giving malicious extensions an unusually privileged position within the software supply chain.

Security teams investigating possible exposure are being urged to inventory installed extensions and versions rather than relying on marketplace listings. VS Code installations can be checked using the command code –list-extensions –show-versions, while project configuration files such as. vscode/extensions. json and development-container configuration files should also be inspected.

Organisations using automated development environments face an additional concern because extensions can be provisioned without developers manually installing them. Container images, virtual desktop templates and CI build systems may therefore continue carrying packages removed from the public registry.