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Bozori.A-E (Zotob.E) Worm

See also Zotob worm

Bozori worm impacted a number of large companies but didn't impact Internet users as extensively as the Blaster and Sasser worm did in 2003 and 2004 respectively.  This happened due to the fact that the vulnerability was Windows 2000 only as well as the method of generation of IP addresses that worked more efficitiently on corporate networks with almost obligatory those days address translation.  Zotob/Bozori might be the fist business worm

QUOTES: There's no question that this worm is spreading. However, it seems to be confined to localized 'explosions' inside large corporations. These organizations, typically made up of 'small internets' behind heavily defended Internet gateways, have experienced infection.

The Bozori incident suggests that we're on the threshold of a new era, in which 'business worms' will cause 'local network outbreaks' in large corporations, but will have little effect on the Internet as a whole.

The main lesson of the initial Zotob epidemics (which is the worst worm epidemics in 2005) is that it's impossible to secure a large PC network from network worms without automated patch management system and no amount of policies, procedures and meetings can change this simple fact.

Application of patches should be automatic for probably 80% of our PC base and manual (user controlled) for other 20% (PCs that contain few applications that proved to be highly "patch sensitive").

Absence of Windows Update Services (WUS) or its alternative (for example, Tivoli patches deployment solutions) in the current many large enterprise IT infrastructure makes corporate  infrastructure a lucrative target for any new network worm that exploits vulnerability if patch  was released by Microsoft less then a month or two (worms authors disassemble the Microsoft patch and use the vulnerability in an already written skeleton code pretty quickly and that was a common theme in several recent successful worms). Actually enterprise users who used Microsoft update services in a guerilla fashion fared the best during the initial Zotob epidemics and were able to continue to work without interruptions.

That's why despite all the efforts in application of the patch MS05-039 during the week of Sept. 15 we were slightly hit by a new variant of the same worm at the end of the last week. This variant was better debugged then prev. one and prey of corporate PCs that still does not have a patch MS05-039 installed. Both variants use the same exploit: Microsoft Windows Plug and Play Buffer Overflow Vulnerability (described in Microsoft Security Bulletin MS05-039) on TCP port 445.

Please note that some new strains of Zotob (Zotob.C ) can spread via email, not just the PnP exploit, although Zotob.E that is discussed below is strictly network worm and does not use e-mail for propagation.

Systems Affected: Windows 2000 only.

Important. PCs that have installed the patch MS05-039 are already protected from any new variant of the worm.

Zotob.E is also known as Bozori.E as F-secure for some reason changed the worm name from Zotob to Bozori (http://www.f-secure.com/v-descs/bozori_a.shtml ). Actually naming of worms/viruses in F-secure is very fuzzy as the product contains several AV engines, each with its own naming conventions. It looks like the name of the virus F-secure prints in the logs depends upon which engine picks up the particular strain of the worm first and the order of engines executions. So, for all discussion below Zotob.E is a synonym of Bozori.A.

Symantec provides the following list of synonyms for the worm:

CME-540, Win32.Tpbot.A [Computer Associates], Bozori [F-Secure], Net-Worm.Win32.Bozori [Kaspersky Lab], W32/Bozori.worm.a!CME-540 [McAfee], W32/Tpbot-A [Sophos], WORM_RBOT.CBQ [Trend Micro]

The worm uses a single executable, a file named wintbp.exe which is around 10,366 bytes. It also creates several files with the prefixes a and tftp and suffix consisting of a random number. If Pc does not have a patch then F-secure can delete the worm and then the PC can be re-infected again and this cycle continue, so there can be a dozen of files with the names like:
c:\winnt\system32\tftp3284

c:\winnt\system32\a4643.exe

c:\winnt\system32\tftp4292

c:\winnt\system32\a9511.exe

c:\winnt\system32\tftp5476

c:\winnt\system32\a9179.exe

 [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
 "Wintbp" = "wintbp.exe"
 

• Port 445 - The worm scans for systems vulnerable to exploit through this port
• Port 69 - TFTP server port on infected systems
• Port 8594 - The command shell port opened by the exploit code

  If the attack is successful a shell (cmd.exe) is started on port 8594. Unlike previous variant this variant of the worm uses tftp instead of ftp. The worm contains a built-in TFTP server listening on port 69.

• F-secure works (patch needs to be applied to prevent reoccurrence of infections).
• Home users can use Symantec removal tool

• http://www.microsoft.com/technet/security/Bulletin/MS05-039.mspx
• What You Should Know About Zotob
• Symantec Security Response - W32.Zotob.E
• F-Secure Computer Virus Information Pages Bozori.A

Webliography

Viruslist.com - Rise of the 'business worm'

Aug 19 2005   |   comment David Emm Senior Technology Consultant, Kaspersky Lab UK

For some time now, Kaspersky Lab has been tracking a shift in virus writers' tactics. The relative decline in the number of global epidemics during the last year signals a move away from the use of mass attacks on users worldwide. Instead, attacks are becoming more localized.

Of course, changing tactics are nothing new in the field of malicious code. Technological advances have always been the chief driving force behind change. The emergence of the Internet as a means of doing business formed the backdrop to the development of Internet-borne malware. The technological 'tug-of-war' between malware authors and security vendors has also influenced the development of malicious code.

However, technology is not the only factor involved. Social dynamics have an equal influence on the direction in which malware develops. The heavy use of social engineering techniques to lure unsuspecting users into running malicious code is just one example of this. The anatomy of the current Bozori worm outbreaks provides another clear example of the social dynamic in malware development.

On the face of it, Bozori is no different to earlier Internet worms like Blaster or Sasser: it uses an exploit to spread directly to vulnerable machines. Yet there's no global epidemic! We've seen no tell-tale signs of an epidemic on the Internet. And we've had no reports of infection from individual users.

There's no question that this worm is spreading. However, it seems to be confined to localized 'explosions' inside large corporations. These organizations, typically made up of 'small internets' behind heavily defended Internet gateways, have experienced infection.

Bozori, it seems, causes local outbreaks, whenever it's able to reach the critical mass (and this is heavily dependent on the level of management in the organization). The worm can't reach many machines over the Internet because these days everybody deploys a firewall. However, a worm can penetrate a local network without going through the firewall: when an infected laptop is brought into a network with, let's say, 50 Windows 2000 machines, chaos erupts. That's why small companies and home users haven't been affected. On the other hand, a number of globally interconnected corporations, running large networks of computers - practically their own reduced versions of the Internet – have been hit badly.

The Bozori incident suggests that we're on the threshold of a new era, in which 'business worms' will cause 'local network outbreaks' in large corporations, but will have little effect on the Internet as a whole.

This trend is not caused by any technical change in the way virus authors code their malware. What has changed is a shift in the social organization or social dynamics. Organizations have been secured behind their 'impenetrable' firewalls, filtering all e-mails and stripping all executable content. Businesses felt secure and confident that no attack could reach them. The blow from the inside was all the worse for being totally unexpected

Suspected Worm Creators Arrested ). It looks like Farid Essebar was the author of Zotob and Mytob as well as the Rbot bot worm:
 

Police in Morocco arrested Farid Essebar, 18, a Moroccan national born in Russia who used the online moniker "Diabl0." Authorities in Turkey arrested 21-year-old Atilla Ekici, known by the online alias "Coder."

... ... ...

Authorities said the pair were using the worms in a money-making scheme and did not appear to have any terrorist connections

... ... ...

Louis M. Reigel III, assistant director of the FBI's Cyber Division, said evidence indicates Ekici paid Essebar to develop the worms and that the two used them for financial gain. Reigel declined to say whether the men were connected to a larger criminal enterprise. But according to information released by the Moroccan government, the two men are alleged to have forwarded financial information stolen from victims' computers to a credit-card fraud ring.

Police who raided Essebar's home found a computer that contained the original programming instructions for the first version of the Zotob worm, according to a law enforcement source who was involved in the investigation but spoke on condition of anonymity because the information could affect legal proceedings in Turkey.

The United States has an extradition agreement with Turkey, but Reigel said the government would not seek to extradite either man. Rather, he said, both countries have specific laws against computer crimes that should allow local authorities to prosecute.