Threat Description

Sober.H

Details

Aliases: Sober.H, I-Worm.Sober.h
Category: Malware
Type:
Platform: W32

Summary


Sober.H appeared on June 11th, 2004. This Sober variant doesn't spread itself in e-mails. Instead, it mass-mails political statements. It might have been downloaded to computers already infected by earlier Sober variant, Sober.G for example.



Removal


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More

Detailed instructions for F-Secure security products are available in the documentation found in the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.



Technical Details


Sober.H is written in Visual Basic. Its file is a PE executable 59747 bytes long, packed with UPX file compressor. Sober.H has its own SMTP engine.

Installation to system

Sober.H's file is started installs itself to system. It copies itself to Windows System folder with a semi-randomly generated name and EXE extension. The following text strings are used to generate the file name of the Sober's executable:

sys  host  dir  expolrer  win  run  log  32  disc  crypt  data  diag  spool  service  smss32   

After that Sober.H creates startup keys for its file in Windows Registry. The key names are also semi-randomly generated from the above given list. The following keys are created:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]  "" = "%WinSysDir%\.exe"  [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]  "" = "%WinSysDir%\.exe"   

During its installation cycle Sober.H creates the following files in Windows System folder:

bcegfds.lll  zhcarxxi.vvx  cvqaikxt.apk  Odin-Anon.Ger   

These files have zero length and they are used to disable previous variants of Sober if they are installed on an infected computer.

Sending e-mails

Sober.H sends different e-mail messages with political statements. It doesn't attach itself to these messages.

Before spamming Sober.H scans files with certain extensions on all hard disks to harvest e-mail addresses. Files with the following extensions are scanned:

pmr  stm  slk  inbox  imb  csv  bak  imh  xhtml  imm  imh  cms  nws  vcf  ctl  dhtm  cgi  pp  ppt  msg  jsp  oft  vbs  uin  ldb  abc  pst  cfg  mdw  mbx  mdx  mda  adp  nab  fdb  vap  dsp  ade  sln  dsw  mde  frm  bas  adr  cls  ini  ldif  log  mdb  xml  wsh  tbb  abx  abd  adb  pl  rtf  mmf  doc  ods  nch  xls  nsf  txt  wab  eml  hlp  mht  nfo  php  asp  shtml  dbx   

The found e-mail addresses and user names are saved in these 2 files that Sober.H creates in Windows System folder:

llsapwin32.dats  mswn32sock.dats   

When Sober.H is active in memory it blocks access to these files as well as to its executable file.

Sober.H ignores e-mail addresses that contain any of the following substrings:

@www  @from.  smtp-  @smtp.  gold-certs  ftp.  .dial.  .ppp.  anyone  subscribe  mantec  announce  @gmetref  sql.  someone  nothing  you@  user@  reciver@  somebody  secure  msdn.  me@  whatever@  whoever@  anywhere  yourname  mustermann@  .kundenserver.  mailer-daemon  variabel  -dav  law2  .sul.t-  .qmail@  t-ipconnect  t-dialin  ipt.aol  time  freeav  @ca.  abuse  winrar  domain.  host.  viren  bitdefender  spybot  detection  icrosoft  ewido.  emsisoft  @foo.  winzip  @example.  bellcore.  @arin  mozilla  @iana  @avp  @msn  @sophos  @panda  @kaspers  free-av  antivir  virus  verizon.  @ikarus.  @nai.  @messagelab  nlpmail01.  clock   
Payload

Sober.H can download and activate an executable file from the following website:

people.freenet.de   

The name of the downloaded executable file is 'winhlpx32ll.exe'.

Deactivation of Sober.H

Sober.H periodically looks for a file named 'sysmms32.lla' and it this file is found, it uninstalls itself from memory. Moreover, if this file is present in Windows System folder, Sober.H does not install itself to a system.



Detection


Detection of Sober.H is available in the following FSAV updates:

Detection Type: PC
Database: 2004-06-11_03



Description Details: Alexey Podrezov; June 11th, 2004


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