Java/CVE-2012-4681

Exploit:Java/CVE-2012-4681 is a family of malicious Java applets that attempt to exploit a vulnerability (CVE-2012-4681) in the Java Runtime Environment (JRE) in order to download and install files of an attacker's choice onto your computer. Oracle Java JDK and JRE 7 Update 5 and earlier, JRE 6 Update 34 are all vulnerable to this exploit. At the time of analysis, we have only seen samples targeting JDK and JRE 7 Update 5 and earlier versions.

To check if you're running a vulnerable version of Java:

1. Go to the control panel (Select Start|Control Panel)
2. Select Programs. If Java is installed you will see it in the list of installed programs. Click it to open the Java Control Panel.
3. On the General tab, click About to see which version of Java you have installed.

Make sure that you install all available updates from the vendor in order to avoid this exploit. You can read more about this vulnerability and download software updates from these links:

• CVE-2012-4681
• Oracle advisory
• Java Download

Note: This detection may be triggered when you visit a website that contains the malicious code. Even if you are not using a vulnerable version of the JRE this detection may be reported when you visit a website that contains the malicious code. This does not mean that you have been compromised, rather that an attempt to compromise your computer has been made.

Threat in context

Java is a general-purpose programming language, but cases of this exploit are targeted against the Java plug-in for web browsers. The intent of the Java plug-in is that Java programs (or "applets") can be offered by websites, and run in a "sandbox" where the Java plug-in enforces rules on what the Java applet can do so that it cannot escape restricted environment.

What is an exploit?

Exploits are written to take advantage of weaknesses (or "vulnerabilities") in legitimate software. A project called "Common Vulnerability Enumeration" (or "CVE"), used by many vendors and organizations, gives each vulnerability a unique number, in this case "CVE-2012-4681". The portion "2012" refers to the year the vulnerability was discovered, and "4681" is a unique ID for this specific vulnerability. The official source that gives out CVE identifiers lists this at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-4681.

Payload

Downloads and installs arbitrary files

If you visit a website containing the malicious code while using a vulnerable version of Java, Exploit:Java/CVE-2012-4681 is loaded. It then attempts to download and execute files from a remote host/URL. The files that are downloaded and executed could be any of the attacker's choice and could include additional malware.

Additional technical details

Exploit:Java/CVE-2012-4681 first appeared in late August 2012 as a 0-day which didn’t have any patches available, as described here. Oracle later released a patch for this vulnerability. The problem lies in a com.sun.beans package in JRE or JDK from Oracle. The package has an improper access check and could be abused to retrieve class and methods from trusted code. After this retrieval of privileged class and methods, they could be abused to set arbitrary security access value for a local access control context. This will enable the malicious Java code to perform malicious activities by performing elevation of privilege.

Exploit:Java/CVE-2012-4681 attacks the security model instead of memory corruption issues. With memory corruption issues, the exploit is dependent on the specific CPU (Central Processing Unit) type and operating systems, and might be affected by mitigation technology like DEP (Data Execution Prevention) or ASLR (Address Space Layout Randomization).

Attacking the security model means that the exploit might be effective on any platform the Java interpreter is on; for example Windows, MacOS, Linux, etc.

Usually the exploits are written using a few Java classes working together. The various class files are bundled into an archive called a JAR, which uses the ZIP file format. Every JAR contains a Manifest.MF file to identify itself to the Java Runtime. Since it is found in every JAR, it won't be listed.

Below are some examples of files that exploit the vulnerability described in CVE-2012-4681:

• 03c55af352edbe6963be10f2ceedc1fc88d9a729
• cve2012xxxx\Gondvv.class
• 060df5f731da509aa4e563974468f761f96e35f1
• aPSQeX.lpl
• FMR.class
• ghCija.class
• jWJEpKio.class
• mupVbo.class
• nJSmoKFre.class
• qseTs.class
• RqTsy.class
• rXntYgPr.class
• SsyAmsW.class
• uhuPhoA.class
• XMRuySlH.class
• yWAIumfA.class
• 0e22f0e3af074831cd7e8c4bb5e78a546bf10b9d
• Bil.class
• Fees.class
• Ini.class
• Ttiik.class
• 13a37e859b3f22e6cda1d8de29d5b5cb48882b63
• attend.class
• curioKue.class
• game.class
• holdsSwearAyins.class
• woeFeel.class
• e9eb6da4ed220687ebeb9fac6a7243d0f9f2bdc2
• aXx.class
• FMWNHS.class
• FnVdVHLO.class
• III.class
• QlbHzGLWj.class
• rQwaQzBSe.class
• sFT.class
• thI.lpl
• UdzJ.class
• Xjtoxffrx.class
• YXRB.class
• zWrDN.class
• d8f81639a35816bd713b638d8cb17338e3c5e6b6
• ulstersBoonsDaze\adoredSyn.class
• ulstersBoonsDaze\antae.class
• ulstersBoonsDaze\game.class
• ulstersBoonsDaze\muLeg.class
• ulstersBoonsDaze\pomQuaBute.class
• d69542d93effed18bf108e35f61d849178e1261b
• gdIUPZhjdQVWPNAndZlUKwQMb.class
• gdiVczjHbUlgsMaREjjtCKCqa.class
• gEsggWWdMoSrwiYpzIvevMyQz.class
• gnMeecGBrylqcYDzRngAHWPWL.class
• gofLGlPkeiJTkFIYHwbgIPbVV.class
• gTScamqeOHJqskxnPErnFMXvw.class
• gturu.class
• gTYlgEvJeemOHmdAdNRyHzqYv.class
• gwTGfiltkOfDdSqsudkOBcVfQ.class
• gWZWWaEvfyKJSLVyJLrtSypSs.class
• gziqTXlQLueoQzKUAaOGNVlfH.class
• c5852083da552b66a32d93d64fe3e06916a4bd18
• a.class
• b.class
• c.class
• d.class
• e.class
• f.class
• g.class
• h.class
• i.class
• pka.class
• 5a7a98d207b108eade765dc98aef82c752e4de01
• billTyphusMana\bravure.class
• billTyphusMana\cagesSwarmed.class
• billTyphusMana\game.class
• billTyphusMana\jakesHandselWoke.class
• billTyphusMana\oohOoze.class

Once the exploit obtains full privileges on your computer, it may:

• Run an executable file (that may be detected as malware) included in the JAR
• Run an executable file from (that may be detected as malware) a URL hard-coded in the exploit's file
• Take instructions from the HTML file (such as a URL to the malware executable) that loaded them

Related information / Related references

The articles referenced below outline some of the the technical details of the weakness this vulnerability exploits:

• Protecting yourself from CVE-2012-4681 Java exploits
• Oracle Security Alert for CVE-2012-4681
• Zero-Day Season is Not Over Yet

Analysis by Jeong Wook (Matt) Oh