Which versions of sidecar-mcp are malicious?

The following npm versions of sidecar-mcp are flagged malicious: 1.0.0, 1.0.1, 1.0.2, 1.0.4. Treat any of these as compromised.

How do I remediate sidecar-mcp if I installed it?

sidecar-mcp establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

I already installed sidecar-mcp — how do I know if it already compromised me?

If sidecar-mcp was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is sidecar-mcp part of a known attack campaign?

Yes — sidecar-mcp is associated with the IN-MAL-2026-009642, IN-MAL-2026-009643, IN-MAL-2026-009645, IN-MAL-2026-009644 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find sidecar-mcp across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for sidecar-mcp (4 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging sidecar-mcp across your stack and pipelines.

Malicious package

sidecar-mcpnpm

Malicious code in sidecar-mcp (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-10161

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall sidecar-mcp

What this malware does

The package ships a single bin entry sidecar-mcp, advertised as a one-command setup for Sidecar MCP servers. When the user runs that command, the CLI appends a hardcoded ed25519 public key (labeled [email protected]) into the running user's ~/.ssh/authorized_keys (created with mode 0o600 if absent) and then runs sudo systemsetup -setremotelogin on, with a launchctl load.../ssh.plist fallback, to enable the macOS SSH daemon. Neither the package description nor the CLI output discloses these actions. The result is persistent inbound SSH access to the installer's machine for the holder of the corresponding private key — a backdoor mechanism that survives reboot and is independent of the package itself remaining installed. The advertised purpose (MCP server setup) does not require modifying authorized_keys or enabling Remote Login, and the installer never consents to granting a third party interactive shell access.

Malicious versions

4 flagged

1.0.01.0.11.0.21.0.4

Indicators of compromise (SHA-256)

421d80be33fb453b40cb46e71d737f543c8caa1b7534edaa4b5bb2a9c23ddd8d

8b48cc2cf1326bc68eda84d3c97733c367be4309d93c9671ad4d36f431bd0353

d5f432bf48fe9d69cc3b91d4814350fb184b491b3cdae34201552ba6338324be

f21cba1f2f8e1cb8ee8cf910892c186eb685ab2c84451f23c85efc589d07623a

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for sidecar-mcp (4 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging sidecar-mcp across your stack and pipelines.
If you installed it — respond
sidecar-mcp establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If sidecar-mcp was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks sidecar-mcp before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. sidecar-mcp on npm has been identified as a malicious package (versions 1.0.0, 1.0.1, 1.0.2, 1.0.4 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-009642IN-MAL-2026-009643IN-MAL-2026-009645IN-MAL-2026-009644

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks sidecar-mcp-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring