How the Mentioned CVE Works:
The vulnerability CVE-2025-1234 in Azle arises due to improper handling of the `setTimer` function in versions 0.27.0, 0.28.0, and 0.29.0. When `setTimer` is invoked, it triggers an infinite loop of timers. Each timer attempts to clean up the global state of the previous timer, but due to a logical flaw, the cleanup process fails to terminate. This results in an endless cycle of timer executions, consuming system resources and rendering the canister unresponsive. The issue is exacerbated because any valid call to `setTimer` can trigger this behavior, making it a critical vulnerability.
DailyCVE Form:
Platform: Azle
Version: 0.27.0, 0.28.0, 0.29.0
Vulnerability: Infinite Loop
Severity: Critical
Date: Mar 14, 2025
What Undercode Say:
Exploitation Details:
1. Exploit Code:
import { setTimer } from 'azle';
// Trigger infinite loop
setTimer(() => {
console.log("Timer executed");
}, 1000);
This code, when executed in vulnerable versions, will cause an infinite loop of timers.
2. Impact:
- Resource exhaustion on the canister.
- Canister becomes unresponsive to further requests.
- Potential denial-of-service (DoS) for applications relying on the canister.
3. Detection:
- Monitor CPU and memory usage spikes on canisters.
- Check for repeated timer-related logs in the canister’s console.
Protection and Mitigation:
1. Patch:
Upgrade to Azle version 0.30.0 or later, where the issue is fixed.
2. Workaround:
- If a canister is already affected, upgrade it to clear all timers.
- Avoid using `setTimer` in vulnerable versions.
3. Code Fix:
// Ensure proper cleanup in the timer callback
setTimer(() => {
console.log("Timer executed");
clearGlobalState(); // Ensure cleanup logic terminates
}, 1000);
4. Monitoring Commands:
- Use `dfx canister status` to check canister health.
- Analyze logs with
dfx canister logs <canister_id>.
5. Preventive Measures:
- Implement rate limiting for timer calls.
- Use automated testing to detect infinite loops during development.
6. Analytics:
- Track timer execution frequency.
- Set up alerts for abnormal resource usage patterns.
By following these steps, developers can exploit, detect, and protect against CVE-2025-1234 effectively.
References:
Reported By: https://github.com/advisories/GHSA-xc76-5pf9-mx8m
Extra Source Hub:
Undercode
