diff --git a/lib/mixlib/archive/tar.rb b/lib/mixlib/archive/tar.rb
index 30c8f9e..dcdb5b9 100644
--- a/lib/mixlib/archive/tar.rb
+++ b/lib/mixlib/archive/tar.rb
@@ -125,7 +125,7 @@ def is_tar_archive?(io)
 
       def read_tar_magic(io)
         io.rewind
-        magic = io.read(512).bytes[257..264].pack("C*")
+        magic = Array(io.read(512).bytes[257..264]).pack("C*")
         io.rewind
         magic
       end
diff --git a/spec/mixlib/tar_spec.rb b/spec/mixlib/tar_spec.rb
index f9e7373..3b4f71a 100644
--- a/spec/mixlib/tar_spec.rb
+++ b/spec/mixlib/tar_spec.rb
@@ -98,6 +98,13 @@
         expect(extractor.send(:is_tar_archive?, raw)).to eq(false)
       end
     end
+    context "invalid small file" do
+      let(:data) { "testdir/#{Array.new(11) { "\x00" }.join}smallfile" }
+      it "does not identify an invalid header in a small file" do
+        extractor = described_class.new(tgz_archive)
+        expect(extractor.send(:is_tar_archive?, raw)).to eq(false)
+      end
+    end
   end
 
 end