🔒 Fix SSRF vulnerability in std.web.fetch - #52
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This commit addresses a Server-Side Request Forgery (SSRF) vulnerability in the `fetch` function of the standard `web` module. Previously, user-provided URLs were passed directly to `ureq::get`, allowing attackers to probe internal networks, access metadata services (like 169.254.169.254), or hit loopback addresses. The fix introduces a custom `SafeResolver` for the `ureq` client that blocks resolution of private, loopback, link-local, broadcast, and unspecified IP addresses (for both IPv4 and IPv6, including IPv4-mapped IPv6 addresses). By doing this at the resolver level, we prevent DNS rebinding (TOCTOU) attacks. Additionally, HTTP redirects are explicitly disabled (`.redirects(0)`) to prevent bypasses where an external safe server redirects to an internal malicious IP. Co-authored-by: Tcode-Motion <188012755+Tcode-Motion@users.noreply.github.com>
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🎯 What: Fixed an SSRF (Server-Side Request Forgery) vulnerability in
⚠️ Risk: Attackers could supply URLs pointing to internal infrastructure (
stdlib/src/web.rswhere thefetchfunction blindly retrieved user-provided URLs.127.0.0.1, AWS metadata169.254.169.254, internal subnets), exposing sensitive internal data, configuration, or performing unauthorized actions on internal APIs.🛡️ Solution: Implemented a robust validation mechanism:
urlcrate to parse and validate incoming URLs.ureq::Resolver(SafeResolver) that filters out all private, loopback, link-local, broadcast, and unspecified IP addresses (IPv4 and IPv6). This resolves the IP at connection time, preventing DNS rebinding (TOCTOU) attacks.ureqHTTP agent with.redirects(0)to prevent attackers from bypassing the check via 3xx redirects to internal IPs.PR created automatically by Jules for task 2495096785143464329 started by @Tcode-Motion