encrypt-data-using-rc4-via-systemfunction032.yml

rule:
  meta:
    name: encrypt data using RC4 via SystemFunction032
    namespace: data-manipulation/encryption/rc4
    authors:
      - richard.weiss@mandiant.com
    scopes:
      static: function
      dynamic: thread
    att&ck:
      - Defense Evasion::Obfuscated Files or Information [T1027]
    mbc:
      - Defense Evasion::Obfuscated Files or Information::Encryption-Standard Algorithm [E1027.m05]
      - Cryptography::Encrypt Data::RC4 [C0027.009]
    references:
      - https://doxygen.reactos.org/df/d13/sysfunc_8c_source.html
      - https://blog.gentilkiwi.com/tag/systemfunction032
    examples:
      - 3BBDF04C25FCD9876733EAA9163B3ED64D81396E7414619758D9376EDF4C103E:0x1000976C # api match
  features:
    - or:
      - api: SystemFunction032
      - and:
        - match: link function at runtime on Windows
        - string: "SystemFunction032"
        - optional:
          - string: /advapi32/i
          - string: /cryptsp/i