Threat Classification
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You can use a simple High, Medium, or Low scale to prioritize threats. If a threat is rated as High, it poses a significant risk to your application and needs to be addressed as soon as possible. Medium threats need to be addressed, but with less urgency. You may decide to ignore low threats depending upon how much effort and cost is required to address the threat.
DREAD (OWASP version)
| Rating | High (10) | ... (9) | Medium (5) | Low (0) | |
|---|---|---|---|---|---|
| D | Damage potential | Complete system or data destruction | Individual user data is compromised or affected. | Nothing | |
| R | Reproducibility | Just a web browser and the address bar is sufficient, without authentication. | One or two steps required, may need to be an authorized user. | Very hard or impossible, even for administrators of the application. | |
| E | Exploitability | Just a web browser | Malware exists on the Internet, or an exploit is easily performed, using available attack tools. | Advanced programming and networking knowledge, with custom or advanced attack tools. | |
| A | Affected users | All users | Some users, but not all | None | |
| D | Discoverability | The information is visible in the web browser address bar or in a form. | Details of faults like this are already in the public domain and can be easily discovered using a search engine. | Can figure it out by guessing or by monitoring network traces. | Very hard to impossible; requires source code or administrative access. |
Table 3.7 shows an example DREAD rating for both threats:
Table 3.7 DREAD rating
| Threat | D | R | E | A | D | Total | Rating |
|---|---|---|---|---|---|---|---|
| Attacker obtains authentication credentials by monitoring the network. | 10 | 10 | 5 | 5 | 5 | (10+10+5+5+5)/5 = 7 | High |
| SQL commands injected into application. | 10 | 10 | 10 | 10 | 5 | (10+10+10+10+5)/5 = 9 | High |
DREAD (Microsoft version)
The problem with a simplistic rating system is that team members usually will not agree on ratings. To help solve this, add new dimensions that help determine what the impact of a security threat really means. At Microsoft, the DREAD model is used to help calculate risk. By using the DREAD model, you arrive at the risk rating for a given threat by asking the following questions:
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| Threat Description | Attacker obtains authentication credentials by monitoring the network |
|---|---|
| Threat target | Web application user authentication process |
| Risk rating | High |
| Attack techniques | Use of network monitoring software |
| Countermeasures | Use SSL to provide encrypted channel |
DREAD (OWASP version)
| Rating | High (10) | Medium (5) | Low (0) | |
|---|---|---|---|---|
| D | Damage potential | Complete system or data destruction | Individual user data is compromised or affected. | Nothing |
| R | Reproducibility | Just a web browser and the address bar is sufficient, without authentication. | One or two steps required, may need to be an authorized user. | Very hard or impossible, even for administrators of the application. |
| E | Exploitability | Just a web browser | Malware exists on the Internet, or an exploit is easily performed, using available attack tools. | Advanced programming and networking knowledge, with custom or advanced attack tools. |
| A | Affected users | All users | Some users, but not all | None |
| D | Discoverability | The information is visible in the web browser address bar or in a form. | Can figure it out by guessing or by monitoring network traces. | Very hard to impossible; requires source code or administrative access. |
Table 3.7 shows an example DREAD rating for both threats:
Table 3.7 DREAD rating