title: "Failed to load Main-Class manifest attribute from client.jar" in a possible malware .jar file?
body: <p>I found a Client.jar file on a customer's computer, containing two .class files which I could decompile to this two files:</p>
  
  <p><a href="http://pastebin.com/yYCC2E89" rel="nofollow">Client.java</a></p>
  
  <p><a href="http://pastebin.com/a684LJcG" rel="nofollow">I.java</a></p>
  
  <p>Moreover there's a I.gif which is obviously no GIF looking at it with a hex editor.</p>
  
  <p>They're obviously obfuscated and I'm not into Java that much. I tried to run in in a VM but it tells me <b>"Failed to load Main-Class manifest attribute from Client.jar"</b></p>
  
  <p>Might be, that the main class is not in the manifest, but how to fix this? <b>Does this mean, it could not be run on the customer's computer?</b></p>
  
  <p>There's also a META-INF folder containing the files MANIFEST.MF, ME.DSA, ME.SF.</p>
  
  <p>MANIFEST.MF looks like that:</p>
  
  <pre><code>Manifest-Version: 1.0
  Created-By: 1.6.0_20 (Sun Microsystems Inc.)
  
  Name: Client.class
  SHA1-Digest: ex7bAth9HYUTIi8EcpeOc1OsVMg=
  
  Name: I/I.class
  SHA1-Digest: 0H6A7/XmOCNhayPI9TwC45Mky4s=
  
  Name: I/I.gif
  SHA1-Digest: AzzSpXaRFMYvtYJvrnFsHQDvJkE=
  </code></pre>
  
  <p>I would like to analyse this further by running it in sandboxie or VM, what does the error mean how can I run it?</p>
  
  <p>It's obviously some sort of malware, so only experts should answer this. Thanks in advance!</p>