Worm:W32/AutoRun.GM

Classification

Malware

Worm

W32

-

Summary

A standalone malicious program which uses computer or network resources to make complete copies of itself.

Automatic action

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.

Suspect a file is incorrectly detected (a False Positive)?

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 detection database 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.

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Submit a sample

Submit a file or URL for further analysis.

Technical Details

Execution

Upon execution, the malware first creates a copy of itself in the program files, then amends the registry to ensure automatic execution.

It also creates the following files in all removable drives found in the system:

  • system.exe
  • autorun.inf

The system.exe file is a copy of itself, while the autorun.inf contains the following strings:

  • [autorun]open=system.exeshellexecute=system.exeshell\Explore\command=system.exeshell\Open\command=system.exeshell=Explore

Downloads

The malware attempts to download files from:

  • http://aaszxt.ru/load4/[...].php?v=1&rs=%VolumeSerialNumber%&n=1&uid=1

Note: %VolumeSerialNumber% is volume serial number that the operating system assigns when a hard disk is formatted.

Stealth

For its stealth routine, it injects malicious code into the one of the following normal process:

  • svchost.exe
  • %program%

Note: %program% is usually "C:\Program Files\Internet Explorer\IEXPLORE.EXE -nohome" which was taken under the registry key "HKEY_CLASSES_ROOT\http\shell\open\command, (Default)".It also removes the hooked addresses corresponding to various NT Functions implemented in Ntoskrnl.exe, then restores them to their original values.

The malware will attempt to make the changes by exploiting the GDI Local Elevation of Privilege Vulnerability (CVE-2006-5758), which in unpatched machines allows a remote attacker to gain direct access to the kernel. If this method fails, it drops and executes a special driver that restores the pointers:

  • NtProtectVirtualMemory
  • NtOpenThread
  • NtTerminateThread
  • NtCreatePort
  • NtConnectPort
  • NtCreateKey
  • NtAdjustPrivilegesToken
  • NtCreateFile
  • NtWriteVirtualMemory
  • NtOpenProcess
  • NtCreateProcess
  • NtCreateProcessEx
  • NtCreateSection
  • NtCreateThread
  • NtDeleteKey
  • NtDeleteValueKey
  • NtDuplicateObject
  • NtEnumerateKey
  • NtEnumerateValueKey
  • NtLoadDriver
  • NtLoadKey
  • NtLoadKey2
  • NtNotifyChangeKey
  • NtOpenFile
  • NtOpenKey
  • NtOpenSection
  • NtQueryKey
  • NtQueryMultipleValueKey
  • NtQueryValueKey
  • NtReplaceKey
  • NtRestoreKey
  • NtResumeThread
  • NtSaveKey
  • NtSetContextThread
  • NtSetInformationFile
  • NtSetInformationKey
  • NtSetSystemInformation
  • NtSetValueKey
  • NtSuspendThread
  • NtSystemDebugControl
  • NtTerminateProcess

The malware creates and executes a kernel service driver as either of the following:

  • %systemdir%\Drivers\%servicename%.sys
  • %service_path_and_filename%

Both these files are detected as Rootkit:W32/Agent.UG.

It will query all services under the following registry entries, to obtain the %service_path_and_filename% and %servicename% of services that have:

  • Service Type = SERVICE_KERNEL_DRIVER and Start= SERVICE_DEMAND_START:
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\%servicename%

It also creates the following registry entries to bypass the Windows Firewall:

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List{malware_executed_path_and_filename} = "{malware_executed_path_and_filename}:*:Enabled:EMOTIONS_EXECUTABLE"

Additionally, it creates a window with Classnames= "WNDCLASSXEMORES".