Yet another NetSky worm variant - NetSky.H was found on 5th of March 2004. This variant is very close to NetSky.G variant. It spreads itself in emails as an executable attachment.This worm contains another, but this time less insulting message for the authors of Bagle and Mydoom. And like its previous variants NetSky.H tries to uninstall Bagle worm variants from an infected computer.
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
Descriptions of all previous NetSky worm variants can be found here:
The worm's file is a PE executable file 22528 bytes long, packed with PE-Pack file compressor. The unpacked file's size is over 28 kilobytes.
On March 8th, 2004 the worm constantly beeps with PC speaker from 11:00 to 11:59. Below is the link to the WAV file with the sound that the worm makes: https://www.f-secure.com/v-pics/netsky_d.wav
NetSky.H worm doesn't copy its files to shared folders.
When run, the worm installs itself to system. It copies its file to Windows folder as MAJA.EXE and creates a startup key for this file in System Registry:
[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] "Antivirus" = "%windir%\maja.exe -antivirus service"
where %windir% represents Windows directory
The worm creates a mutex named "MI[SkyNet.cz]SystemsMutex" to avoid running more than one instance of itself.
NetSky.H worm has its own SMTP engine that it uses to send emails with infected attachments to all found email addresses. The worm uses different subjects, message body texts and attachment names in its emails.
The worm scans all available drives except CD-ROM drives for emails. It searches for email addresses in files with the following extensions:
.eml .txt .php .pl .htm .html .vbs .rtf .uin .asp .wab .doc .adb .tbb .dbx .sht .oft .msg .shtm .cgi .dhtm
The subject for infected messages is selected from the following list:
Re: Samples Re: Document Re: Approved Re: Here the file Re: Yours Re: Your file Re: Your folder Re: Your encrypted file Re: Hi Re: Hello Re: Appending Re: Index Re: Your data Re: Your application Re: Part 2 Re: Part 3 Re: Secound Part Re: Zipped folder Re: My details Re: Your details Re: Your bill Re: Your PIN Re: Your TAN Re: Your loveletter Re: Your picture Re: Your briefing
The message body text for infected messages is selected from the following list:
Your document is attached. Here is the file. See the attached file for details. Please have a look at the attached file... Please read the attached file. Your file is attached.
The attachment name for infected messages is selected from the following list:
your_smaples.scr your_document.scr document.scr message_part2.scr your_document.scr document_full.scr your_picture.pif message_details.scr your_file.scr your_picture.scr document_4351.scr yours.scr mp3music.scr application.scr all_document.scr my_details.scr document_excel.scr document_word.scr my_details.scr your_details.scr your_bill.scr your_pin_88.scr your_tan_33.scr your_letter.scr your_pic.scr your_briefing.scr
The worm avoids sending emails to email addresses that contain any of the following substrings:
icrosoft antivi ymantec spam avp f-secur itdefender orman cafee aspersky f-pro orton fbi abus messagelabs skynet andasoftwa freeav sophos antivir iruslis
The NetSky.H worm variant of the worm deletes the following Registry keys:
[HKCR\CLSID\{E6FB5E20-DE35-11CF-9C87-00AA005127ED}\InProcServer32] [HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\PINF] [HKLM\System\CurrentControlSet\Services\WksPatch] [HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices]
system. [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
KasperskyAv
Explorer
Taskmon
system.
msgsvr32
DELETE ME
service
Sentry
Windows Services Host [HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
KasperskyAv
Explorer
OLE
Windows Services Host
d3dupdate.exe
au.exe
sysmon.exe
rate.exe
gouday.exe
sate.exe
ssate.exe
srate.exe
NetSky.H worm removes Registry keys of several Bagle worm variants if it finds them on an infected computer. At least the last 8 keys listed above belong to earlier Bagle variants.