CAPEC-9 - Buffer Overflow in Local Command-Line Utilities

This attack targets command-line utilities available in a number of shells. An attacker can leverage a vulnerability found in a command-line utility to escalate privilege to root.

Severity

Likelihood

Confidentiality

Integrity

Availability

  • Attack Methods 2
  • Injection
  • API Abuse
  • Purposes 1
  • Penetration
  • Sec Principles 3
  • Reluctance to trust
  • Defense in Depth
  • Least Privilege
  • Scopes 5
  • Gain privileges / assume identity
  • Authorization
  • Access_Control
  • Confidentiality
  • Execute unauthorized code or commands
  • Availability
  • Integrity
  • Confidentiality
  • Modify memory
  • Integrity
  • DoS: crash / exit / restart
  • Availability
  • Read memory
  • Confidentiality

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 a command-line utility to the user.

The command-line utility exposed by the target host has a buffer overflow vulnerability that can be exploited.

The attacker can probe for services available on the target host. Many services may expose a command utility. For instance Telnet is a service which can be invoked through a command shell.

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

Step 1 -

Attacker identifies command utilities exposed by the target host..


Step 1 -

On the probing stage, the attacker interacts with the command utility and observes the results of its input. The attacker's goal is to uncover a buffer overflow in the command utility. For instance the attacker may find that input data are not properly validated..


Step 1 -

The attacker finds a buffer overflow vulnerability in the command utility and tries to exploit it. He crafts malicious code and injects it using the command utility. The attacker can at worst execute remote code on the target host..


Carefully review the service's implementation before making it available to user. For instance you can use manual or automated code review to uncover vulnerabilities such as buffer overflow.

Use a language or compiler that performs automatic bounds checking.

Use an abstraction library to abstract away risky APIs. Not a complete solution.

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.

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

Apply the latest patches to your user exposed services. This may not be a complete solution, especially against a zero day attack.

Do not unnecessarily expose services.