What attacks can a high-defense CDN actually prevent? From DDoS to CC attacks, and API endpoints being bombarded with requests, many websites still become unavailable even after using a regular CDN. Today, we will systematically explain the protection logic of high-defense CDNs, applicable business scenarios, and how companies can determine if they need to deploy one, based on real attack techniques. This is suitable for cross-border e-commerce, gaming, and global business.

Many people first hear about "high-defense CDN" after their website has been attacked.

Suddenly, the site becomes slow to access, interfaces become unresponsive, users cannot log in, or pages simply won't open—initially thought to be a server failure, but after much investigation, it turns out it wasn't the server crashing, but an attack.

Then, a more practical question arises: What exactly can a high-defense CDN defend against? Is it really effective?

This article will not beat around the bush; we'll start directly from how attacks happen and how they are intercepted.

I. The Most Common Type: "Bandwidth-Saturating" DDoS Attacks

DDoS stands for Distributed Denial of Service. The name sounds complex, but the principle is easy to understand.

Imagine that normally 3-5 guests arrive at your door at a time, and you can greet them normally. But if suddenly 100 people surge in, all wanting to sit in your living room, your entrance, living room, and bathroom will quickly become overwhelmed. DDoS attacks work similarly, using a large number of "zombie computers" (infected computers) to simultaneously send requests to the target server, exhausting the server's bandwidth, CPU, memory, and other resources.

This is the most "simple and crude" attack method.

Simply put: A large number of machines (zombies, botnets) send requests to your server together, directly clogging the bandwidth.

The result is: the website cannot be opened, the server times out, and a large number of users go offline.

This type of attack does not rely on skill, but mainly on "volume."

How does a high-defense CDN block it?

Core capabilities are mainly two:

1) Large-scale traffic scrubbing: Divert attack traffic to high-defense nodes and perform filtering at the edge.

2) Load distribution: Use global nodes to share access pressure, preventing the attack from concentrating on a single node or origin.

Simply put: It's not that your server suddenly became stronger, but rather that a "flood barrier" was placed in front of it.

II. The Most Frustrating: CC Attacks

CC attack stands for Challenge Collapsar. Just hearing the name tells you it's unfriendly.

The biggest difference between a CC attack and a DDoS attack is that CC attacks are more "precise." They do not necessarily require large traffic; instead, they disguise themselves as normal user behavior, persistently requesting pages or interfaces that consume high resources.

Typical characteristics of CC attacks include:

• • Traffic volume may not be large, but requests are very dense
• • Superficially similar to normal user access
• • Targeting resource-intensive functions
• • Hard to solve with simple rate limiting

If DDoS is like "flooding," then CC attacks are more like "pretending to be normal people waiting in line."

Attackers simulate real user operations, such as: opening pages, clicking to log in, repeatedly searching, requesting interfaces

Each request looks "legitimate."

The result:

• Server CPU gradually maxes out
• Database connections are exhausted
• Page response times slow down continuously

How does a high-defense CDN block it?

This type of attack is not about who has more bandwidth, but more about "recognition ability."

High-defense CDNs typically perform:

• Behavioral analysis (access frequency, path, dwell time)
• Fingerprint identification (browser characteristics)
• Rate limiting or blocking of abnormal requests

To put it simply: It doesn't just look at "who you are," but judges "whether you look like a real user."

Solutions like CDN07 have made this capability a "dynamic policy" rather than relying on fixed rules.

III. Increasingly Common: API Interface Attacks

Modern websites rely heavily on interfaces: login API, payment API, data query API.

Attackers no longer target just pages; they directly target these "critical entry points."

For example: brute force login, bombarding captcha APIs, invoking order queries.

This type of attack is characterized by: Traffic may not be large, but it is highly destructive.

Because it attacks the "business core."

How does a high-defense CDN block it?

This mainly relies on: Rate limiting, token verification, and request behavior recognition.

Another critical capability needed: Distinguishing between "normal user calls" and "script calls."

IV. Often Overlooked: Malicious Crawlers and Script Traffic

There is another type of attack that may not immediately bring down the website but gradually "drains" it.

For example: continuously scraping website content, scanning API structures, analyzing business logic.

Short-term impacts may seem insignificant, but long-term effects include: bandwidth consumption, service slowdowns, and data structure leaks.

How does a high-defense CDN block it?

Mainly relies on:

• Bot recognition (whether it's an automated tool)
• Behavioral pattern analysis
• Blacklists and dynamic blocking

Many high-defense solutions classify such access directly as "risk traffic" for processing.

V. Mixed Attacks: The Most Common and Hardest to Handle

In real attack scenarios, single methods are rarely used anymore.

Common combinations include:

• First, use DDoS to saturate bandwidth
• Then, use CC to overwhelm the API
• Finally, attack logins or payments

The goal is clear: To keep you off guard and eventually bring the whole system down.

How does a high-defense CDN block it?

This tests "system capability":

• Traffic scrubbing
• Behavioral recognition
• Dynamic policy switching
• Multi-node scheduling

It is not a single point function, but a complete protection system.

VI. Why Do Some High-Defense CDNs "Seem Effective but Fail in Practice"?

To be honest, this industry is not without depth.

Common issues include:

• Stated protection capabilities are high, but lack real scrubbing ability
• Few nodes, easily penetrated when under attack
• Only protects against large traffic, not effective against CC
• Lacks policy scheduling, relies only on fixed rules

So you see a phenomenon: It seems fine normally, but collapses when attacked.

VII. What Does a High-Defense CDN Essentially Do?

To sum up in one sentence: The essence of a high-defense CDN is to "block attacks outside your server."

Specifically:

• Perform traffic scrubbing at edge nodes
• Identify abnormal requests
• Only allow "clean traffic" back to the origin

Your server ultimately receives "filtered access."

Finally:

Many companies only start seriously studying security protection when:

• The website is already down
• Users are complaining
• Revenue has dropped significantly

But the reality is: Attacks will not notify you in advance; they happen suddenly.

You may not need to choose the most expensive solution initially, but at least you need to understand one thing: Can your current architecture withstand a real attack?

If you are not sure, then this capability will eventually need to be added.

FAQ

1. What is the difference between a high-defense CDN and a regular CDN?

The most direct difference: A regular CDN is mainly for acceleration, while a high-defense CDN is for "withstanding attacks."

A regular CDN mainly does: cache static resources, improve access speed.

A high-defense CDN additionally provides: traffic scrubbing (against DDoS), behavioral recognition (to intercept CC attacks), and hiding the origin server IP.

Many websites "using CDN still get taken down"—the root cause is that they used the wrong type.

2. Can a high-defense CDN completely prevent all attacks?

No, but it can withstand the vast majority of "real-world attacks."

To be honest: No protection can be 100% absolutely secure.

But a high-defense CDN can:

• Block large-scale traffic attacks at the outer layer
• Filter out abnormal requests
• Make normal user access almost imperceptibly affected

The true goal is not "no attacks at all," but: Even under attack, business can still operate normally.

3. Is a high-defense CDN really useful when a website is under DDoS attack?

Yes, and it is currently one of the most mainstream solutions.

The reason is straightforward:

• DDoS relies on "using traffic to overwhelm the target"
• High-defense CDNs have larger bandwidth pools and scrubbing capabilities

They divert attack traffic to edge nodes for processing, rather than letting your origin server take the brunt.

In other words: You are not fighting the attacker alone with your resources; you are using the platform's resources to counter them.

4. Why are CC attacks harder to defend against than DDoS?

Because they "look like normal users on the surface."

For example: opening a page, clicking a button, requesting an API.

Every action appears legitimate, just with abnormal access frequency.

Traditional protection often only looks at IP or traffic volume, but CC attacks may: distribute IPs, control access rhythm, and simulate browser behavior.

Thus, preventing CC is not about bandwidth, but about: recognition ability and strategy capability.

5. Which websites or businesses are suitable for a high-defense CDN?

If you are still deciding, refer to these typical scenarios:

• Cross-border e-commerce (most likely to be attacked)
• Gaming/Apps (many interfaces, concentrated attacks)
• SaaS platforms (high stability requirements)
• Websites with login/payment functions

There is also a very practical criterion: If your site has already been attacked, you likely need a high-defense CDN.

6. What level of DDoS attack can a high-defense CDN typically handle?

There is no fixed answer, but you can refer to this logic:

• Small providers: tens of Gbps to hundreds of Gbps
• Medium providers: hundreds of Gbps to 1 Tbps
• Large platforms: Tbps level or higher

But the key is not the number, but: Whether it is "actually usable," not just "nice numbers on paper."

Services like CDN07 emphasize "real attack resistance" and dynamic scheduling, rather than simply listing bandwidth.

7. When should you consider using a high-defense CDN?

Many people wait until "after something goes wrong" to act.

But a more reasonable way to decide:

You should consider it when you encounter:

• The website starts to have stable traffic
• Business relies on online conversions
• There have been abnormal accesses or attack records
• Users have clear stability requirements

Ultimately: A high-defense CDN is not a last-minute firefighting tool; it's infrastructure.