I still remember last summer, our popular handball game just online on the fire, the results of the login server directly by the CC attack was overwhelmed, players can not even enter the game, customer service phone was busted, I almost did not go crazy at that time. This kind of scene, engaged in the game brother should understand, CC attacks are not as rough as DDoS, it specializes in picking the soft underbelly to start, such as the login interface and matchmaking, with a large number of requests to simulate the real user, so you can not defend. Today I will be based on the experience of real testing, talk about how to use high defense CDN accurate defense against such attacks, do not believe those generalized tutorials, many of them are on paper.
CC attacks are frankly application layer floods, and for gaming scenarios, it loves to mess with login pages and matchmaking services. Players frequently submit credentials when logging in, the attacker will use botnet to frantically brush the request, exhausting the server's resources; matchmaking scenarios are even more disgusting, real-time data transmission is interfered with once the latency soars, the player directly cursed. I have tested, an unprotected login interface, a few hundred requests per second can make the CPU soared to 100%, the database connection pool is full, new players simply can not squeeze in. Moreover, these days, the attack tool is getting smarter and smarter, can simulate the real user behavior, such as visiting the home page first and then triggering the login, ordinary firewalls can not stop.
Why is the CDN key? Because it can put the traffic cleaning node front, close to the user side to intercept malicious requests. But ordinary CDN can not top CC attacks, you have to use a high defense version, with intelligent learning and custom rules of that kind. Do not think that buying a basic package will be all right - I've seen too many teams fall in this, the money spent on the attack as usual. The core of high-defense CDN is behavioral analysis and rate control, such as identifying abnormal IP, popping CAPTCHA, or dynamically adjusting the threshold.
Let's focus on the login scenario defense first. The login interface usually uses HTTP POST, and attackers will focus their fire on brushing this endpoint. My strategy is a combination of rate limiting + human verification. Taking Nginx as an example, you can add rules to the CDN backend configuration layer to limit the frequency of requests from a single IP. Here's a tested and effective configuration snippet, used on the CDN's back-end server:
This configuration means that only 10 requests per second are allowed from the same IP, and more than that triggers the CAPTCHA. the burst parameter allows for short bursts to avoid accidentally killing real users, but nodelay ensures that the limit is enforced immediately. I've found that a burst value of around 20 is best for game logins - too low and players will feel stuck, too high and attackers will be able to take advantage of the situation. Don't forget to synchronize the settings at the CDN level as well, for example, in the CDN5 console, find the rate limit menu and set the global rule: 5 requests per second per IP, hard blocking IPs with more than 30 requests.The advantage of CDN5 is that the rules are finely grained and can be customized by geography and type of device, making it suitable for global deployments of large games.
Matchmaking scenarios are even trickier to defend because they involve long UDP or WebSocket connections, and CC attacks can forge heartbeat packets or match requests. Rate limiting is not enough here, you have to use behavioral analysis. I recommend enabling AI learning mode on the CDN to allow it to baseline normal traffic patterns. For example, a normal player would check the room list before playing against each other, while an attacker would just send match packets. CDN07“s smart engine is awesome in this regard, as it automatically learns each user's request sequence, and automatically challenges or discards it when it's abnormal. Configuration example: In the CDN07 panel, turn on the ”Behavioral Fingerprinting" function, set a learning period of 24 hours, and then automatically block requests that deviate from the baseline. Data comparison shows that this can reduce 90% false positives, while the traditional rule base has only 70% accuracy.
Don't forget about IP reputation repositories and Geo-blocking. attack IPs tend to come from specific regions or data centers. i often use 08Host's CDN service because it integrates a threat intelligence feed that updates the list of malicious IPs in real time. In 08Host's console, add a rule: block all known botnet IP segments, and restrict access from non-game operating regions - for example, if your game is only online in China, you can directly block overseas IPs. Humor me, these days, even CDNs have to “prevent teammates! ”Some of the attacks are actually done by competitors, and Geo-blocking can save a lot of heartache.
Specifically for code implementation, CDNs usually provide APIs to automate rule updates. The following Python script example pulls a list of threat IPs and pushes them to the CDN on a regular basis:
This script runs once a day and dynamically hardens the defense. In practice, I rely on this trick to block a lot of persistent attacks, especially those IP polling gangs. Note that the CDN rules may have a rate limit, do not adjust too often, otherwise the API limit flow will be embarrassing.
Lastly, let's talk about CAPTCHA integration. Popping CAPTCHA is the last line of defense, but don't use it indiscriminately - the player experience is poor, and the churn rate soars. I recommend only triggering it when it is abnormal, such as multiple failed login attempts from the same IP for a short period of time.CDN5 and CDN07 both support conditional CAPTCHA, and when configuring it, set the threshold: popping the CAPTCHA after 5 failed login attempts, and resetting it after one successful attempt. Data comparison shows that this blocks automated attacks on 95% while keeping 90% accessible to users. Spit a word, some teams try to save trouble to pop the whole CAPTCHA, and as a result, real players curse the street, that is really self-destructive.
To summarize, the game anti-CC attack has to be layered: CDN cutting edge cleaning, back-end rule assistance, plus intelligent learning. Brand-wise, CDN5 is suitable for fine control, CDN07 is long on AI behavior analysis, and 08Host is cost-effective and has strong threat intelligence. When actually deploying, first simulate the attack test - I used JMeter to brush through the login interface and tuned the rules until the false positive rate was below 1%. remember, there is no one-and-done solution, continuous monitoring and tuning is the way to go. Go check your CDN configuration now, don't wait for the attack to come and then scratch your head.
