GHSA-w5r6-mcgq-7pq4
Yamcs has No Rate Limiting on Authentication Endpoint
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Maven | org.yamcs:yamcs-core | < 5.12.7 | 5.12.7 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
The authentication endpoint `POST /auth/token` in `yamcs-core` lacks any form of rate limiting, account lockout, or failed attempt throttling. As a result, an unauthenticated remote attacker can perform unlimited password guessing attempts against any user account.
This missing rate limiting vulnerability (CWE-307) significantly increases the risk of successful brute-force attacks.
### Root Cause
**File:** `yamcs-core/src/main/java/org/yamcs/http/auth/AuthHandler.java`
`POST /auth/token` has no rate limiting, no lockout after failed attempts, and no CAPTCHA. The handler processes unlimited authentication requests without any throttling mechanism:
```java
// AuthHandler.java — handleToken()
// No throttle, no failed attempt counter, no lockout
private void handleToken(HandlerContext ctx) {
...
getSecurityStore().login(token).whenComplete((info, err) -> {
// Directly attempts authentication with no rate check
});
}
```
This is absent by default — the official quickstart and documentation contain no guidance on configuring rate limiting.
### Impact
An attacker can make unlimited authentication attempts against any account. This enables efficient brute-force attacks against any account.
### Proof of Concept
```bash
# 20 attempts — zero rate limiting
for i in $(seq 1 20); do
curl -s -o /dev/null -w "Attempt $i: HTTP %{http_code}\n" \
-X POST "http://TARGET:8090/auth/token" \
-d "grant_type=password&username=operator&password=operator12$i"
done
# All return HTTP 401 — no HTTP 429 ever
```
**Confirmed:** 20 attempts in 0.07 seconds, no rate limiting enforced.
### Fix
Implement DRF-style throttling on `/auth/token`:
```java
// Track failed attempts per IP
private static final Cache<String, Integer> FAILED_ATTEMPTS =
CacheBuilder.newBuilder().expireAfterWrite(15, TimeUnit.MINUTES).build();
private static final int MAX_ATTEMPTS = 10;
private void handleToken(HandlerContext ctx) {
String ip = ctx.getRemoteAddress();
int attempts = Optional.ofNullable(FAILED_ATTEMPTS.getIfPresent(ip)).orElse(0);
if (attempts >= MAX_ATTEMPTS) {
throw new TooManyRequestsException("Rate limit exceeded");
}
// ... existing auth logic
// On failure: FAILED_ATTEMPTS.put(ip, attempts + 1)
}
```
References
External links from the advisory. They lead to third-party sites.