When the EMF attachment is opened the exploit triggers, which
results in a chain-reaction of droppers. The following files are
created in the Windows System directory:
- SP00LSV.EXE - main dropper that drops the rest of the files
- Alerter.exe - copy of the main dropper
- Alerter16.exe - copied there during network infection
- SPC.EXE - Backdoor dropper
- SCardSer.exe - Backdoor injector
- comsock.dll (renamed to comwsock.dll) - Backdoor injector
- sockup.dll (renamd to dmsock.dll) - Main backdoor component
- SPTRES.DLL - Network propagation routines
SPTRES.DLL is injected into EXPLORER.EXE, comsock.dll is injected
into LSASS.EXE and dmsock.dll is injected into a number of other
processes (eg. IEXPLORE.EXE, OUTLOOK.EXE, etc).
The network propagation routine of Aler is very simple. It scans
random IP addresses for Windows computers. If it finds one, the worm
attempts to connect to it using user credentials from the infected
computer as well as a list of predefined passwords (eg. 1234, pass,
etc). If the connection is successful the Aler copies the main
dropper to the remote computer as
then starts them as a service.
The payload of Aler is a TCP proxy that allows the attacker
to initiate network connections through the infected computer.
This feature could be used to send SPAM, attack other computers,
The backdoor components of Aler are detected as Backdoor.Win32.Small.bq.
Detection for this malware was published on November 11th, 2004
in the following F-Secure Anti-Virus updates:
Detection for the MS04-032 exploit was added on October 22nd, 2004
in update version
Gergely Erdelyi, November 16th, 2004;