diff --git a/.github/workflows/security_hook_linux.yml b/.github/workflows/security_hook_linux.yml
new file mode 100644
index 0000000..9ee75d5
--- /dev/null
+++ b/.github/workflows/security_hook_linux.yml
@@ -0,0 +1,104 @@
+name: Security Hook on Linux
+
+on: [pull_request]
+
+jobs:
+  capture:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+    - name: Update cache
+      run: sudo apt-get update
+    - name: Install system dependencies
+      run: |
+        sudo apt-get install -qq libguestfs0 libguestfs-dev \
+          libguestfs-tools pkg-config libvirt-dev libvirt-daemon-system
+    - name: Allow user to read the kernel for supermin (libguestfs)
+      run: sudo chmod 644 /boot/vmlinuz-*
+    - name: Start libvirt
+      run: sudo systemctl restart libvirtd
+    - name: Define oswatcher pool in qemu:///session
+      run: |
+        virsh -c qemu:///session pool-define-as oswatcher --type dir --target $HOME/images
+        virsh -c qemu:///session pool-build oswatcher
+        virsh -c qemu:///session pool-start oswatcher
+    - name: Set up Python 3.7
+      uses: actions/setup-python@v1
+      with:
+        python-version: '3.7'
+    - name: Install OSWatcher pip dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install .
+        pip install lxml
+        pip install http://download.libguestfs.org/python/guestfs-1.40.2.tar.gz
+    - name: Download import_libvirt script
+      run: |
+        wget 'https://raw.githubusercontent.com/Wenzel/packer-templates/474ea0fa9c540303c8655b521424a8860872b13d/import_libvirt.py'
+        chmod +x import_libvirt.py
+    - name: Download template_domain XML
+      run: wget 'https://raw.githubusercontent.com/Wenzel/packer-templates/474ea0fa9c540303c8655b521424a8860872b13d/template_domain.xml'
+    - name: Download ubuntu-6.06-server image
+      run: wget 'https://www.dropbox.com/s/vv8di5zd2sqhv3k/ubuntu-6.06-server.qcow2?dl=1' -O $HOME/ubuntu-6.06-server.qcow2
+    - name: Import ubuntu-6.06-server in Libvirt
+      run: python import_libvirt.py --uri qemu:///session --domain-type qemu --open-vnc --pool oswatcher --pool-path $HOME/images $HOME/ubuntu-6.06-server.qcow2
+    - name: Refresh oswatcher pool
+      run: virsh -c qemu:///session pool-refresh oswatcher
+    - name: Configure hooks.json
+      run: |
+        cat << EOF > hooks.json
+        {
+            "configuration":
+            {
+                "neo4j": {
+                    "enabled": true,
+                    "delete": false,
+                    "replace": false
+                },
+                "desktop_ready_delay": 0
+            },
+            "hooks":
+            [
+                {
+                    "name": "hooks.filesystem.LibguestfsHook"
+                },
+                {
+                    "name": "hooks.filesystem.FilesystemHook",
+                    "configuration":
+                    {
+                        "enumerate": true,
+                        "log_progress": true,
+                        "log_progress_delay": 10
+                    }
+                },
+                {
+                    "name": "hooks.filesystem.Neo4jFilesystemHook"
+                },
+                {
+                    "name": "hooks.security.SecurityHook",
+                    "configuration": {
+                        "keep_failed_binaries": true,
+                        "keep_failed_dir": "$HOME/checksec_failed"
+                    }
+                }
+            ]
+        }
+        EOF
+    - name: display hooks.json
+      run: cat hooks.json
+    - name: Update path to include checksec
+      run:  echo "::add-path::$GITHUB_WORKSPACE/tools/checksec"
+    - name: Capture ubuntu-6.06-server filesystem
+      run: oswatcher -c qemu:///session ubuntu-6.06-server hooks.json -d
+
+    services:
+      neo4j:
+        image: neo4j:3.4
+        ports:
+          - 7687:7687
+        env:
+          NEO4J_AUTH: "neo4j/admin"
diff --git a/.github/workflows/security_hook.yml b/.github/workflows/security_hook_windows.yml
similarity index 99%
rename from .github/workflows/security_hook.yml
rename to .github/workflows/security_hook_windows.yml
index a605674..54becfb 100644
--- a/.github/workflows/security_hook.yml
+++ b/.github/workflows/security_hook_windows.yml
@@ -1,4 +1,4 @@
-name: Security Hook
+name: Security Hook on Windows
 
 on: [pull_request]
 
diff --git a/hooks/filesystem.py b/hooks/filesystem.py
index 0cbc05a..ad34089 100644
--- a/hooks/filesystem.py
+++ b/hooks/filesystem.py
@@ -6,6 +6,7 @@
 import time
 from collections import Counter
 from pathlib import Path
+from typing import Optional
 
 import guestfs
 import magic
@@ -49,7 +50,7 @@ def close(self):
 
     @property
     @functools.lru_cache()
-    def str_path(self):
+    def str_path(self) -> str:
         return str(self.path)
 
     @property
@@ -94,14 +95,14 @@ def inode_type_value(self):
 
     @property
     @functools.lru_cache()
-    def local_file(self):
+    def local_file(self) -> str:
         STATS['local_file'] += 1
         self._tmp_local_file = TEMPFILE.NamedTemporaryFile()
         self._gfs.download(self.str_path, self._tmp_local_file.name)
         return self._tmp_local_file.name
 
     @functools.lru_cache()
-    def filecmd_output(self, mime_option=False):
+    def filecmd_output(self, mime_option=False) -> Optional[str]:
         """Run the file utility and returns the output"""
         if not self.inode_type == InodeType.REG:
             return None
@@ -113,7 +114,7 @@ def filecmd_output(self, mime_option=False):
 
     @property
     @functools.lru_cache()
-    def gfs_file(self):
+    def gfs_file(self) -> Optional[str]:
         if not self.inode_type == InodeType.REG:
             return None
         STATS['guestfs_file'] += 1
@@ -121,7 +122,7 @@ def gfs_file(self):
 
     @property
     @functools.lru_cache()
-    def file_magic_type(self):
+    def file_magic_type(self) -> Optional[str]:
         """this method is faster than py_magic_type, since it doesn't involve
         downloading the whole file to the host"""
         STATS['file_magic_type'] += 1
@@ -139,7 +140,7 @@ def file_magic_type(self):
 
     @property
     @functools.lru_cache()
-    def py_magic_type(self):
+    def py_magic_type(self) -> Optional[str]:
         if not self.inode_type == InodeType.REG:
             return None
         STATS['py_magic_type'] += 1
diff --git a/hooks/security.py b/hooks/security.py
index 1cfa44f..31091a4 100644
--- a/hooks/security.py
+++ b/hooks/security.py
@@ -66,7 +66,7 @@ def __init__(self, parameters):
         else:
             os_id = self.context.domain.name()
         default_checksec_failed_dir = Path.cwd() / f"{os_id}_checksec_failed"
-        self.keep_binaries_dir = self.configuration.get('keep_failed_dir', default_checksec_failed_dir)
+        self.keep_binaries_dir = Path(self.configuration.get('keep_failed_dir', default_checksec_failed_dir))
 
         self.context.subscribe('detected_os_info', self.get_os_info)
         self.context.subscribe('filesystem_new_file', self.check_file)
@@ -82,6 +82,8 @@ def check_file(self, event):
             # checksec only supports ELF files
             return
         mime = inode.file_magic_type
+        if not mime:
+            return
         filepath = inode.path
         if re.match(r'application/x(-pie)?-(executable|sharedlib)', mime):
             self.logger.info('Checking security of %s: %s', filepath, mime)