Threat Encyclopedia

JAVA_BYTEVER.A

Malware type: JavaScript

Aliases: Trojan.Java.ClassLoader.d (Kaspersky), Trojan.ByteVerify (Symantec), JS/OpenConnect.J.3 (Avira), Troj/Femad-E (Sophos),

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 98, ME, NT, 2000, XP, Server 2003

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

Medium

Distribution potential:

Low

Description: 

This malware is a component of a malicious Java archive file (JAR) that resides in a malicious Web site. System affected by the malware JS_FORTNIGHT.B are redirected to this Web site.

This malware calls and executes another malware, JAVA_JJBLACK.C, which results in modifications to the browser and registry settings of the infected system.

This is Trend Micro's detection for JAVA classes that exploit a known vulnerability in Microsoft Virtual Machine in Windows Operating Systems and Internet Explorer. This flaw allows malicious users to execute codes of his or her choice when a user visits an infected Web site. Notably, users of Sun JVM are not affected by this malware.

For more information on the said vulnerability, please refer to the following Web pages:

For additional information about this threat, see:

Description created: May. 23, 2003 9:25:02 PM GMT -0800
Description updated: Mar. 8, 2005 12:56:26 AM GMT -0800


TECHNICAL DETAILS


File type: Script

Memory resident:  No

Size of malware: 896 Bytes

Initial samples received on: May 24, 2003

Vulnerability used:  (MS03-011) Flaw in Microsoft VM Could Enable System Compromise (816093)

Related toJAVA_JJBLACK.C, JS_FORTNIGHT.B

Payload 1: Executes other malware

Details:

This malware exploits a known vulnerability in Microsoft Virtual Machine build 5.0.3809 and below. This security vulnerability does not correctly check for the presence of certain malicious code when a Java applet is being loaded. Thus, an attacker can exploit this in Web pages that, when viewed or opened, could launch an executable file. Notably, users of Sun JVM are not affected by this malware.

This malware is a component of a malicious Java archive file (JAR) that resides in a malicious Web site. Systems affected with the malware JS_FORTNIGHT.B are redirected to this Web site.

This malware calls and executes another malware, JAVA_JJBLACK.C, which results in modifications to the browser and registry settings of the infected system.

By itself, it has no destructive routine, but it may execute a destructive file in the user’s system when a user visits an infected Web site. It affects all builds of the Microsoft VM up to and including build 5.0.3809.

For more information on the said vulnerability, please refer to the following Web pages:

Revision History:

First pattern file version: 2.274.01
First pattern file release date: May 24, 2003
 
Aug 8, 2006 - Modified Virus Report

SOLUTION


Minimum scan engine version needed: 7.500

Pattern file needed: 2.474.00

Pattern release date: Mar 8, 2005


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

Note: To fully remove all associated malware, perform the clean solutions for the following:

Resetting Internet Explorer Home Page and Search Page

This procedure restores the Internet Explorer home page and search page to the default settings.

  1. Close all Internet Explorer windows.
  2. Open Control Panel. Click Start>Settings>Control Panel.
  3. Double-click the Internet Options icon.
  4. In the Internet Properties window, click the Programs tab.
  5. Click the Reset Web Settings… button.
  6. Select Also reset my home page. Click Yes.
  7. Click OK.

Changing the Signature of Microsoft Outlook Express

This procedure restores the signature of Microsoft Outlook Express.

  1. Open Microsoft Outlook Express.
  2. Click on Tools>Options. Click on the Signature Tab.
  3. If the file chosen in the File text box below is equal to "s.htm" or some other undesired file, delete the entry in the textbox.
  4. Click OK.

Important Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected computers.

Users running other Windows versions can proceed with the succeeding solution set(s).

Running Trend Micro Antivirus

If you are currently running in safe mode, please restart your computer normally before performing the following solution.

Scan your computer with Trend Micro antivirus and delete files detected as JAVA_BYTEVER.A. To do this, Trend Micro customers must download the latest virus pattern file and scan their computer. Other Internet users can use HouseCall, the Trend Micro online virus scanner.

Applying a Patch

This malware exploits a known vulnerability in Windows. Download and install the fix patch supplied by Microsoft. Refrain from using this product until the appropriate patch has been installed. Trend Micro advises users to download critical patches upon release by vendors.

Note: To users who want to download Sun JVM, please proceed to the following Web page:




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