# Decrypting C2 traffic with known key

Some leaked copies of Cobalt Strike have the RSA keypair already generated. If the operator does not generate a new key pair by deleting the old one and restarting the teamserver, defenders can use the leaked private key to decrypt the C2 traffic.

The tool to check for known private keys is at <https://blog.didierstevens.com/2021/10/11/update-1768-py-version-0-0-8/>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://codex-7.gitbook.io/codexs-terminal-window/blue-team/detecting-cobalt-strike/decrypting-c2-traffic-with-known-key.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.