diff --git a/capa/features/extractors/common.py b/capa/features/extractors/common.py
index b706868f..450fb636 100644
--- a/capa/features/extractors/common.py
+++ b/capa/features/extractors/common.py
@@ -28,7 +28,7 @@ def extract_format(buf):
 
 def extract_arch(buf):
     if buf.startswith(b"MZ"):
-        yield from capa.features.extractors.pefile.extract_file_arch(pefile.PE(data=buf), "hack: path not provided")
+        yield from capa.features.extractors.pefile.extract_file_arch(pe=pefile.PE(data=buf))
 
     elif buf.startswith(b"\x7fELF"):
         with contextlib.closing(io.BytesIO(buf)) as f:
diff --git a/capa/features/extractors/pefile.py b/capa/features/extractors/pefile.py
index 2c60499b..3e5d97fd 100644
--- a/capa/features/extractors/pefile.py
+++ b/capa/features/extractors/pefile.py
@@ -20,15 +20,12 @@ from capa.features.extractors.base_extractor import FeatureExtractor
 logger = logging.getLogger(__name__)
 
 
-def extract_file_embedded_pe(pe, file_path):
-    with open(file_path, "rb") as f:
-        fbytes = f.read()
-
-    for offset, i in capa.features.extractors.helpers.carve_pe(fbytes, 1):
+def extract_file_embedded_pe(buf, **kwargs):
+    for offset, _ in capa.features.extractors.helpers.carve_pe(buf, 1):
         yield Characteristic("embedded pe"), offset
 
 
-def extract_file_export_names(pe, file_path):
+def extract_file_export_names(pe, **kwargs):
     base_address = pe.OPTIONAL_HEADER.ImageBase
 
     if hasattr(pe, "DIRECTORY_ENTRY_EXPORT"):
@@ -43,7 +40,7 @@ def extract_file_export_names(pe, file_path):
             yield Export(name), va
 
 
-def extract_file_import_names(pe, file_path):
+def extract_file_import_names(pe, **kwargs):
     """
     extract imported function names
     1. imports by ordinal:
@@ -75,7 +72,7 @@ def extract_file_import_names(pe, file_path):
                     yield Import(name), imp.address
 
 
-def extract_file_section_names(pe, file_path):
+def extract_file_section_names(pe, **kwargs):
     base_address = pe.OPTIONAL_HEADER.ImageBase
 
     for section in pe.sections:
@@ -87,21 +84,18 @@ def extract_file_section_names(pe, file_path):
         yield Section(name), base_address + section.VirtualAddress
 
 
-def extract_file_strings(pe, file_path):
+def extract_file_strings(buf, **kwargs):
     """
     extract ASCII and UTF-16 LE strings from file
     """
-    with open(file_path, "rb") as f:
-        b = f.read()
-
-    for s in capa.features.extractors.strings.extract_ascii_strings(b):
+    for s in capa.features.extractors.strings.extract_ascii_strings(buf):
         yield String(s.s), s.offset
 
-    for s in capa.features.extractors.strings.extract_unicode_strings(b):
+    for s in capa.features.extractors.strings.extract_unicode_strings(buf):
         yield String(s.s), s.offset
 
 
-def extract_file_function_names(pe, file_path):
+def extract_file_function_names(**kwargs):
     """
     extract the names of statically-linked library functions.
     """
@@ -111,17 +105,17 @@ def extract_file_function_names(pe, file_path):
     return
 
 
-def extract_file_os(pe, file_path):
+def extract_file_os(**kwargs):
     # assuming PE -> Windows
     # though i suppose they're also used by UEFI
     yield OS(OS_WINDOWS), 0x0
 
 
-def extract_file_format(pe, file_path):
+def extract_file_format(**kwargs):
     yield Format(FORMAT_PE), 0x0
 
 
-def extract_file_arch(pe, file_path):
+def extract_file_arch(pe, **kwargs):
     if pe.FILE_HEADER.Machine == pefile.MACHINE_TYPE["IMAGE_FILE_MACHINE_I386"]:
         yield Arch(ARCH_I386), 0x0
     elif pe.FILE_HEADER.Machine == pefile.MACHINE_TYPE["IMAGE_FILE_MACHINE_AMD64"]:
@@ -130,20 +124,20 @@ def extract_file_arch(pe, file_path):
         logger.warning("unsupported architecture: %s", pefile.MACHINE_TYPE[pe.FILE_HEADER.Machine])
 
 
-def extract_file_features(pe, file_path):
+def extract_file_features(pe, buf):
     """
     extract file features from given workspace
 
     args:
       pe (pefile.PE): the parsed PE
-      file_path: path to the input file
+      buf: the raw sample bytes
 
     yields:
       Tuple[Feature, VA]: a feature and its location.
     """
 
     for file_handler in FILE_HANDLERS:
-        for feature, va in file_handler(pe, file_path):
+        for feature, va in file_handler(pe=pe, buf=buf):
             yield feature, va
 
 
@@ -170,7 +164,10 @@ class PefileFeatureExtractor(FeatureExtractor):
         return self.pe.OPTIONAL_HEADER.ImageBase
 
     def extract_file_features(self):
-        for feature, va in extract_file_features(self.pe, self.path):
+        with open(self.path, "rb") as f:
+            buf = f.read()
+
+        for feature, va in extract_file_features(self.pe, buf):
             yield feature, va
 
     def get_functions(self):
diff --git a/capa/features/extractors/smda/extractor.py b/capa/features/extractors/smda/extractor.py
index 1bd7f351..1a13653b 100644
--- a/capa/features/extractors/smda/extractor.py
+++ b/capa/features/extractors/smda/extractor.py
@@ -26,7 +26,7 @@ class SmdaFeatureExtractor(FeatureExtractor):
         return self.smda_report.base_addr
 
     def extract_file_features(self):
-        for feature, va in capa.features.extractors.smda.file.extract_features(self.smda_report, self.path):
+        for feature, va in capa.features.extractors.smda.file.extract_features(self.smda_report, self.buf):
             yield feature, va
         yield from self.global_features
 
diff --git a/capa/features/extractors/smda/file.py b/capa/features/extractors/smda/file.py
index 0be6aa0a..fe901bea 100644
--- a/capa/features/extractors/smda/file.py
+++ b/capa/features/extractors/smda/file.py
@@ -8,24 +8,22 @@ from capa.features.file import Export, Import, Section
 from capa.features.common import String, Characteristic
 
 
-def extract_file_embedded_pe(smda_report, file_path):
-    with open(file_path, "rb") as f:
-        fbytes = f.read()
-
-    for offset, i in capa.features.extractors.helpers.carve_pe(fbytes, 1):
+def extract_file_embedded_pe(buf, **kwargs):
+    for offset, _ in capa.features.extractors.helpers.carve_pe(buf, 1):
         yield Characteristic("embedded pe"), offset
 
 
-def extract_file_export_names(smda_report, file_path):
-    lief_binary = lief.parse(file_path)
+def extract_file_export_names(buf, **kwargs):
+    lief_binary = lief.parse(buf)
+
     if lief_binary is not None:
         for function in lief_binary.exported_functions:
             yield Export(function.name), function.address
 
 
-def extract_file_import_names(smda_report, file_path):
+def extract_file_import_names(smda_report, buf):
     # extract import table info via LIEF
-    lief_binary = lief.parse(file_path)
+    lief_binary = lief.parse(buf)
     if not isinstance(lief_binary, lief.PE.Binary):
         return
     for imported_library in lief_binary.imports:
@@ -41,8 +39,8 @@ def extract_file_import_names(smda_report, file_path):
                     yield Import(name), va
 
 
-def extract_file_section_names(smda_report, file_path):
-    lief_binary = lief.parse(file_path)
+def extract_file_section_names(buf, **kwargs):
+    lief_binary = lief.parse(buf)
     if not isinstance(lief_binary, lief.PE.Binary):
         return
     if lief_binary and lief_binary.sections:
@@ -51,21 +49,18 @@ def extract_file_section_names(smda_report, file_path):
             yield Section(section.name), base_address + section.virtual_address
 
 
-def extract_file_strings(smda_report, file_path):
+def extract_file_strings(buf, **kwargs):
     """
     extract ASCII and UTF-16 LE strings from file
     """
-    with open(file_path, "rb") as f:
-        b = f.read()
-
-    for s in capa.features.extractors.strings.extract_ascii_strings(b):
+    for s in capa.features.extractors.strings.extract_ascii_strings(buf):
         yield String(s.s), s.offset
 
-    for s in capa.features.extractors.strings.extract_unicode_strings(b):
+    for s in capa.features.extractors.strings.extract_unicode_strings(buf):
         yield String(s.s), s.offset
 
 
-def extract_file_function_names(smda_report, file_path):
+def extract_file_function_names(smda_report, **kwargs):
     """
     extract the names of statically-linked library functions.
     """
@@ -75,25 +70,24 @@ def extract_file_function_names(smda_report, file_path):
     return
 
 
-def extract_file_format(smda_report, file_path):
-    with open(file_path, "rb") as f:
-        yield from capa.features.extractors.common.extract_format(f.read())
+def extract_file_format(buf, **kwargs):
+    yield from capa.features.extractors.common.extract_format(buf)
 
 
-def extract_features(smda_report, file_path):
+def extract_features(smda_report, buf):
     """
     extract file features from given workspace
 
     args:
       smda_report (smda.common.SmdaReport): a SmdaReport
-      file_path: path to the input file
+      buf: the raw bytes of the sample
 
     yields:
       Tuple[Feature, VA]: a feature and its location.
     """
 
     for file_handler in FILE_HANDLERS:
-        for feature, va in file_handler(smda_report, file_path):
+        for feature, va in file_handler(smda_report=smda_report, buf=buf):
             yield feature, va
 
 
diff --git a/capa/features/extractors/viv/file.py b/capa/features/extractors/viv/file.py
index c92e124e..db3738bd 100644
--- a/capa/features/extractors/viv/file.py
+++ b/capa/features/extractors/viv/file.py
@@ -18,17 +18,17 @@ from capa.features.file import Export, Import, Section, FunctionName
 from capa.features.common import String, Characteristic
 
 
-def extract_file_embedded_pe(vw, buf):
-    for offset, i in pe_carve.carve(buf, 1):
+def extract_file_embedded_pe(buf, **kwargs):
+    for offset, _ in pe_carve.carve(buf, 1):
         yield Characteristic("embedded pe"), offset
 
 
-def extract_file_export_names(vw, buf):
-    for va, etype, name, _ in vw.getExports():
+def extract_file_export_names(vw, **kwargs):
+    for va, _, name, _ in vw.getExports():
         yield Export(name), va
 
 
-def extract_file_import_names(vw, buf):
+def extract_file_import_names(vw, **kwargs):
     """
     extract imported function names
     1. imports by ordinal:
@@ -62,12 +62,12 @@ def is_viv_ord_impname(impname: str) -> bool:
         return True
 
 
-def extract_file_section_names(vw, buf):
+def extract_file_section_names(vw, **kwargs):
     for va, _, segname, _ in vw.getSegments():
         yield Section(segname), va
 
 
-def extract_file_strings(vw, buf):
+def extract_file_strings(buf, **kwargs):
     """
     extract ASCII and UTF-16 LE strings from file
     """
@@ -78,7 +78,7 @@ def extract_file_strings(vw, buf):
         yield String(s.s), s.offset
 
 
-def extract_file_function_names(vw, buf):
+def extract_file_function_names(vw, **kwargs):
     """
     extract the names of statically-linked library functions.
     """
@@ -88,7 +88,7 @@ def extract_file_function_names(vw, buf):
             yield FunctionName(name), va
 
 
-def extract_file_format(vw, buf):
+def extract_file_format(buf, **kwargs):
     yield from capa.features.extractors.common.extract_format(buf)
 
 
@@ -105,7 +105,7 @@ def extract_features(vw, buf: bytes):
     """
 
     for file_handler in FILE_HANDLERS:
-        for feature, va in file_handler(vw, buf):
+        for feature, va in file_handler(vw=vw, buf=buf):
             yield feature, va