mandiant / mandiant/capa-rules

create process suspended

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false positive
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Description

## Summary

`create process suspended`: a sample with a large basic block that includes `CreateProcessAsUserW` and the number `4` is resulting in a FP for this rule.

## Examples

`574f3513f6d7e15f102e82e4d35bf164:0x404E4F`

## Possible improvements

Identify function arguments and refine rules so that, in this case, one could specify the number must be an argument to the function. Another thought: the ability to state a rule element (e.g., number) must be within X bytes (before, after, or both) of the API call.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by examining the `create process suspended` rule and the sample `574f3513f6d7e15f102e82e4d35bf164:0x404E4F`, focusing on the `CreateProcessAsUserW` call and the number `4`. Investigate how function arguments and byte proximity can be represented in the rule system. Done means this sample no longer produces a false positive while intended detections remain covered.

Written by the indexing model from the issue text.

Assessment

Domain
reverse-engineering
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

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