# Comparing Common Vulnerabilities

> Markdown source of <https://docs.calebsargeant.com/networking/cisco/core-security/security-concepts/01.-comparing-common-vulnerabilities/>.

## Software Bugs & Buffer Overflow

An attacker can write over data and can also obtain unauthorised data.

### Software Bug

Flaw in computer program that causes the program to behave in a way that was not intended.

### Buffer Overflow

A Buffer is a reservation of memory for a specific size. An Overflow is when the size of data is greater than the reservation.

## Weak Passwords & Hard Coded Passwords

### Strong Passwords

- Complex and long
- 12 to 16 character minimum
- A-Z, a-z, 0-9, !@#\$%

Also:

- No dictionary words
- Replacing letters with special characters or numbers doesn’t provide much security
- Change passwords

### Hard Coded Passwords

Passwords embedded in software code. Once attacker knows the password, they can compromise any system that uses the program.

**Mitigations:**

- Store passwords outside of application in encrypted file
- Could prompt for initial password
- Match against hashes, not the actual password

**Inbound HCP:** Credentials used for access to program

**Outbound HCP:** Application uses password to access other application

## Missing Encryption

### Encryption

- Provides confidentiality and integrity
- VPNs are used for data in transit
- Makes it difficult
  - to gain access
  - to manipulate data

If data is missing encryption, it leaves the data exposed

## Path Traversal

Allows attacker to navigate outside of original directory (www.test.com/../../etc/password.file). Attacker can use error messages to figure out the structure.

**Mitigations:**

- Work without user input if possible
- Blacklist special characters
- Mask the structure by using indexes
  - Enter ID 10
  - Back end will navigate to Nebraska directory

## SQL Injection

- Use a tool to inject malicious code into legitimate code.
- Easy to discover - Internet search can provide a lot of info
- Prevalence is common
- Easy to exploit
- Impacts can be severe

**Impact:**

- Successful attack can reveal usernames and passwords, PII, and sensitive corporate info.
- Can modify data
  - Create additional accounts
  - Create fake, damaging information
- Can bring down the system
  - Attacker can remove necessary files

## Cross Site Scripting & Cross Site Forgery Request

### Cross Site Scripting

- Inject malicious code in order to control behavior of the site
- Embed the code in a link
  - Attacker sends the link to the victim
  - Can shorten the URL to disguise it
- Persistent XSS
  - Changes the code on the server
  - Each visitor that visits the site runs the malicious code

**Mitigations:**

- Use a security encoding library
- Don’t allow untrusted data in vulnerable areas of website code

### Cross Site Forgery Request

- Takes advantage of legitimate Cross Site Requests
  - Causes victim to run actions on an already authenticated session
  - Runs code in the background unbeknownst to the victim
  - May transfer money from an online bank

**Mitigations:**

- Mitigate XSS
- Secure random tokens
- Have users utilise a browser that supports SameSite cookie attributes