CAPEC-8 - Buffer Overflow in an API Call

This attack targets libraries or shared code modules which are vulnerable to buffer overflow attacks. An attacker who has access to an API may try to embed malicious code in the API function call and exploit a buffer overflow vulnerability in the function's implementation. All clients that make use of the code library thus become vulnerable by association. This has a very broad effect on security across a system, usually affecting more than one software process.






  • Attack Methods 2
  • API Abuse
  • Injection
  • Purposes 1
  • Penetration
  • Sec Principles 2
  • Reluctance to trust
  • Defense in Depth
  • Scopes 4
  • DoS: crash / exit / restart
  • Availability
  • Execute unauthorized code or commands
  • Availability
  • Integrity
  • Confidentiality
  • Read memory
  • Confidentiality
  • Modify memory
  • Integrity

Low level: An attacker can simply overflow a buffer by inserting a long string into an attacker-modifiable injection vector. The result can be a DoS.

High level: Exploiting a buffer overflow to inject malicious code into the stack of a software system or even the heap can require a higher skill level.

The target host exposes an API to the user.

One or more API functions exposed by the target host has a buffer overflow vulnerability.

Step 1 -

An attacker can call an API exposed by the target host..

Step 2 -

On the probing stage, the attacker injects malicious code using the API call and observes the results. The attacker's goal is to uncover a buffer overflow vulnerability..

Step 1 -

The attacker finds a buffer overflow vulnerability, crafts malicious code and injects it through an API call. The attacker can at worst execute remote code on the target host..

Bound checking should be performed when copying data to a buffer.

Use a language or compiler that performs automatic bounds checking.

Use secure functions not vulnerable to buffer overflow.

If you have to use dangerous functions, make sure that you do boundary checking.

Compiler-based canary mechanisms such as StackGuard, ProPolice and the Microsoft Visual Studio /GS flag. Unless this provides automatic bounds checking, it is not a complete solution.

Use OS-level preventative functionality. Not a complete solution.