mandiant / mandiant/capa

Dynamic call scope: add a feature for extracting repeated api calls

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dynamic enhancement
Dominant language
Python
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Forks
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Avg merge
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Merged PRs (30d)
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Description

CAPE provides the number of times an api call was repeated. This might be useful for rule authors (detecting API hammering, profiling malware fa)

I propose either adding a `repeated` feature, or adding a `characteristic("api-hammering")` feature.

of the two I feel like the first would be better, since if we opt for a characteristic feature we'd need to define the minimal bound for the repeats, which I feel like would be variant across samples/families (not sure about this however).

Example rule:

```yaml
rule:
meta:
name: API hammering
scopes:
dynamic: thread
examples:
- 83e921d6368baade50bb2a1031efd6bc # Nymaim
features:
- call:
- api: EnumDisplaySettingsA
- repeated: 500 or more
```

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

The issue names no files or tests. Start by tracing CAPE's repeated API-call count into capa's dynamic thread scope, then compare the proposed `repeated` feature with the alternative characteristic approach. Done should include a decided design and a working API-hammering rule using the proposed behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
reverse-engineering, security
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
32/100

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