diff --git a/rehlds/msvc/ReHLDS.vcxproj b/rehlds/msvc/ReHLDS.vcxproj
index 2aaab88..3baf06a 100644
--- a/rehlds/msvc/ReHLDS.vcxproj
+++ b/rehlds/msvc/ReHLDS.vcxproj
@@ -273,6 +273,9 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release Swds Play|Win32'">true</ExcludedFromBuild>
     </ClCompile>
     <ClCompile Include="..\unittests\rehlds_tests_shared.cpp" />
+    <ClCompile Include="..\unittests\security_tests.cpp">
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug Swds|Win32'">true</ExcludedFromBuild>
+    </ClCompile>
     <ClCompile Include="..\unittests\struct_offsets_tests.cpp">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug Swds|Win32'">true</ExcludedFromBuild>
diff --git a/rehlds/msvc/ReHLDS.vcxproj.filters b/rehlds/msvc/ReHLDS.vcxproj.filters
index 1c3350b..a8e0c27 100644
--- a/rehlds/msvc/ReHLDS.vcxproj.filters
+++ b/rehlds/msvc/ReHLDS.vcxproj.filters
@@ -349,6 +349,9 @@
     <ClCompile Include="..\engine\sse_mathfun.cpp">
       <Filter>engine</Filter>
     </ClCompile>
+    <ClCompile Include="..\unittests\security_tests.cpp">
+      <Filter>unittests</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\hookers\memory.h">
diff --git a/rehlds/unittests/security_tests.cpp b/rehlds/unittests/security_tests.cpp
new file mode 100644
index 0000000..ebf67eb
--- /dev/null
+++ b/rehlds/unittests/security_tests.cpp
@@ -0,0 +1,61 @@
+#include "precompiled.h"
+#include "rehlds_tests_shared.h"
+#include "cppunitlite/TestHarness.h"
+
+TEST(IsSafeFileExtension, SecurityChecks, 1000)
+{
+	struct testdata_t
+	{
+		const char* filename;
+		bool safe;
+	};
+
+	testdata_t testdata[] = {
+		{"radio/go.wav", true},
+		{"radio/go.WAV", true},
+		{"textures.wad", true},
+#ifdef REHLDS_FIXES
+		{"!QWERTY", true},
+		// TODO:
+		//{"file.dll2", true},
+		//{"noext", false},
+		//{".hidden", false},
+		//{"subdir/.hidden", false},
+#else
+		{"file.dll2", false},
+#endif
+		{"../file.txt", false},
+		{"/home/file.txt", false},
+		{"C:/Windows/file.txt", false},
+		{"models\\terror.mdl", false},
+		{"file~.mdl", false},
+		{"file.wav.", false},
+		{"file.dll.txt", false},
+		{"halflife.wad", false},
+		{"pak0.pak", false},
+		{"xeno.wad", false},
+		{"file.cfg", false},
+		{"file.lst", false},
+		{"file.exe", false},
+		{"file.vbs", false},
+		{"file.com", false},
+		{"file.bat", false},
+		{"file.dll", false},
+		{"file.ini", false},
+		{"file.log", false},
+		{"file.so", false},
+		{"file.dylib", false},
+		{"file.sys", false},
+		{"file.SYS", false},
+	};
+
+	for (int i = 0; i < ARRAYSIZE(testdata); i++) {
+		testdata_t* d = &testdata[i];
+		bool result = IsSafeFileToDownload(d->filename);
+
+		char msg[256];
+		Q_snprintf(msg, sizeof msg, "IsSafeFileToDownload(%s) check", d->filename);
+		CHECK(msg, result == d->safe);
+	}
+
+}