Description

zrok: Unauthenticated DoS via unbounded memory allocation in striped session cookie parsing Summary endpoints.GetSessionCookie parses an attacker-supplied cookie chunk count and calls make([]string, count) with no upper bound before any token validation occurs. The function is reached on every request to an OAuth-protected proxy share, allowing an unauthenticated remote attacker to trigger gigabyte-scale heap allocations per request, leading to process-level OOM termination or repeated goroutine panics. Both publicProxy and dynamicProxy are affected.

Attack Vector: Network — exploitable via a single HTTP request with a crafted Cookie header.

Attack Complexity: Low — no preconditions or chaining required; the attacker only needs to know the cookie name (publicly derivable from any OAuth redirect).

Privileges Required: None — reached before JWT validation or any authentication check.

User Interaction: None.

Scope: Unchanged — impact is confined to the affected proxy process.

Confidentiality Impact: None.

Integrity Impact: None.

Availability Impact: High — sustained or concurrent requests cause OOM process termination, taking down the proxy for all users of all shares it serves.

Affected Components

endpoints/oauthCookies.go — GetSessionCookie (line 81)

endpoints/publicProxy/authOAuth.go — handleOAuth (line 50) — call site, pre-auth

endpoints/dynamicProxy/cookies.go — getSessionCookie (line 29) — call site

Mitigation

Aliases

References