Ensure path traversal and arbitrary filesystem access are prevented

ВисокаНиво 1Аутоматскаmcp-server

Опис

The server normalizes and canonicalizes every filesystem path supplied as a tool or resource parameter before any access-control check or filesystem operation. Canonicalization resolves symbolic links, for example os.path.realpath() in Python or fs.realpathSync() in Node.js, before comparing the resolved path against the configured allowlist of approved directories. Symlink bypass and ../ directory traversal are two independent attack paths, and each is guarded. The read is rejected unless the resolved real path is the approved root itself or a descendant of it, compared by path component and not by string prefix, so an approved root such as /srv/approved does not admit a sibling such as /srv/approved_evil. Every rejected attempt is logged as a security event. Without canonicalization, a ../ sequence or a symlink can resolve to a file outside the approved scope while passing a naive c...

Како се проверава

Метод провере: Команда љуске

shell

cfg="${MCP_CONFIG:-/etc/mcp/server.json}"; [ -f "$cfg" ] || { echo "missing $cfg (set MCP_CONFIG)"; exit 1; }; grep -Eq '"cis_5_4_1"|"protocolVersion"|"capabilities"|"auth"' "$cfg" && echo compliant || echo "non-compliant: section 5.4.1"

Очекивани излаз: compliant

Како се исправља

Метод исправке: Смерница или закрпа инфраструктуре

Configure the server's path-handling middleware to canonicalize every supplied path, resolving symlinks and ../ via realpath or realpathSync, before any access check. Reject the read unless the resolved real path is the approved root or a descendant of it, compared by path component rather than by string prefix, and log rejected attempts as security events. Set the approved directories in server configuration. For defense in depth, add kernel-enforced confinement that resolves beneath the root without following symlinks, and apply the OS-level isolation Recommendations in Section 9. This is server middleware, so there is no portable command for the canonicalization logic itself.

Својства

Оперативни системи: Било који
Ознаке: access-controlaimcpmcp-server
Референца: CIS MCP Server Benchmark v1.0.0 - 5.4.1 Ensure path traversal and arbitrary filesystem access are prevented

Проверите овај рачунар

Покрените ово на рачунару за који имате дозволу за проверу. Скенирање ради у режиму само за читање.

shell

tmaegis scan --target mcp-server