What is Predictable from Observable State (CWE-341)?

TL;DR: Predictable from Observable State (CWE-341) is a type of vulnerability that occurs when a number or object is predictable based on observations about the system or network. You can prevent it by following best practices such as verifying return values and testing your code thoroughly.

At-a-Glance

What is Predictable from Observable State?

Predictable from Observable State (CWE-341) is a type of vulnerability that occurs when a number or object is predictable based on observations about the system or network. As defined by the MITRE Corporation under CWE-341, and classified by the OWASP Foundation as not directly mapped.

Quick Summary

Predictable from Observable State can have significant consequences, including unauthorized access to sensitive information or systems. It’s essential to follow best practices such as verifying return values and testing your code thoroughly to prevent this vulnerability.

Jump to: What is Predictable from Observable State? · Quick Summary · Predictable from Observable State Overview · How Predictable from Observable State Works · Business Impact of Predictable from Observable State · Predictable from Observable State Attack Scenario · How to Detect Predictable from Observable State · How to Fix Predictable from Observable State · Framework-Specific Fixes for Predictable from Observable State · How to Ask AI to Check Your Code for Predictable from Observable State · Predictable from Observable State Best Practices Checklist · Predictable from Observable State FAQ · Vulnerabilities Related to Predictable from Observable State · References · Scan Your Own Site

Predictable from Observable State Overview

What: Predictable from Observable State (CWE-341) is a type of vulnerability that occurs when a number or object is predictable based on observations about the system or network.

Why it matters: The consequences of Predictable from Observable State can vary depending on the context, but may include unauthorized access to sensitive information or systems.

Where it occurs: This vulnerability can occur in any system or network where there are observable states that can be used to predict numbers or objects.

Who is affected: Any user or entity that interacts with the system or network may be affected by this vulnerability.

Who is NOT affected: Users who do not interact with the system or network, and systems that do not have observable states that can be used to predict numbers or objects.

How Predictable from Observable State Works

Root Cause

Predictable from Observable State occurs when a number or object is predictable based on observations about the system or network. This can happen due to various reasons such as lack of randomness, poor entropy sources, or insecure protocols.

Attack Flow

1. An attacker observes the system or network and identifies observable states that can be used to predict numbers or objects.
2. The attacker uses this information to gain unauthorized access to sensitive information or systems.

Prerequisites to Exploit

• Observable states that can be used to predict numbers or objects
• Lack of randomness, poor entropy sources, or insecure protocols

Vulnerable Code

import random
random_number = random.randint(1, 100)

This code is vulnerable because it uses the randint() function from the random module, which can produce predictable numbers.

Secure Code

import secrets
random_number = secrets.randbelow(101)

This code is secure because it uses the secrets module, which provides a cryptographically secure way to generate random numbers.

Business Impact of Predictable from Observable State

Confidentiality: Unauthorized access to sensitive information or systems can lead to confidentiality breaches.

Integrity: Predictable from Observable State can also lead to integrity breaches if an attacker uses this vulnerability to modify sensitive data.

Availability: This vulnerability can also affect the availability of systems or networks if an attacker uses it to disrupt service.

Some real-world business consequences include:

• Financial losses due to unauthorized access to sensitive information
• Compliance issues due to confidentiality and integrity breaches
• Reputation damage due to public disclosure of security incidents

Predictable from Observable State Attack Scenario

1. An attacker observes the system or network and identifies observable states that can be used to predict numbers or objects.
2. The attacker uses this information to gain unauthorized access to sensitive information or systems.

How to Detect Predictable from Observable State

Manual Testing

• Verify return values and testing your code thoroughly
• Use tools such as grep or sed to search for predictable patterns in code

Automated Scanners (SAST/DAST)

• PenScan’s automated scan engines can detect Predictable from Observable State vulnerabilities
• Static analysis tools can identify predictable patterns in code

PenScan Detection

PenScan’s scanner engines actively test for this issue.

False Positive Guidance

• Be cautious when interpreting results, as some tools may produce false positives due to similar-looking code patterns.

How to Fix Predictable from Observable State

• Increase the entropy used to seed a PRNG
• Use products or modules that conform to FIPS 140-2
• Re-seed the PRNG periodically using high-quality sources

Framework-Specific Fixes for Predictable from Observable State

Java

import java.security.SecureRandom;
SecureRandom random = new SecureRandom();
int randomNumber = random.nextInt(101);

This code uses the SecureRandom class to generate a cryptographically secure random number.

Node.js

const crypto = require('crypto');
const randomNumber = crypto.randomBytes(4).readUInt32LE(0) % 101;

This code uses the crypto module to generate a cryptographically secure random number.

How to Ask AI to Check Your Code for Predictable from Observable State

You can use an AI coding assistant like this:

Review the following Python code block for potential CWE-341 Predictable from Observable State vulnerabilities and rewrite it using primary fix technique: import secrets; randomNumber = secrets.randbelow(101)

Predictable from Observable State Best Practices Checklist

✅ Use cryptographically secure random number generators ✅ Verify return values and testing your code thoroughly ✅ Increase the entropy used to seed a PRNG ✅ Re-seed the PRNG periodically using high-quality sources

Predictable from Observable State FAQ

How is Predictable from Observable State defined?

Predictable from Observable State (CWE-341) is a type of vulnerability that occurs when a number or object is predictable based on observations about the system or network.

What are the consequences of Predictable from Observable State?

The consequences of Predictable from Observable State can vary depending on the context, but may include unauthorized access to sensitive information or systems.

How can I detect Predictable from Observable State in my code?

You can use manual testing and automated scanners to detect Predictable from Observable State in your code.

What are some common mitigations for Predictable from Observable State?

Common mitigations for Predictable from Observable State include increasing the entropy used to seed a PRNG, using products or modules that conform to FIPS 140-2, and re-seeding the PRNG periodically using high-quality sources.

How can I prevent Predictable from Observable State in my code?

You can prevent Predictable from Observable State by following best practices such as verifying return values and testing your code thoroughly.

What are some related vulnerabilities to Predictable from Observable State?

Some related vulnerabilities to Predictable from Observable State include CWE-340, Generation of Predictable Numbers or Identifiers (ChildOf).

Where can I learn more about Predictable from Observable State and its mitigation?

You can learn more about Predictable from Observable State and its mitigation by visiting the MITRE Corporation’s website for CWE-341.

Vulnerabilities Related to Predictable from Observable State

References

• https://cwe.mitre.org/data/definitions/341.html
• NVD

Scan Your Own Site

Manual code review catches what you know to look for. An automated scan catches what you didn’t. Scan your own website using PenScan to find Predictable from Observable State and other risks before an attacker does.