Shruggle: вирус под Windows 64-bit (AMD64)

[fear factor]

Корпорация Symantec вчера обновила информацию о вирусе W64.Shruggle.1318, который инфицирует 64-битные Windows-системы на базе платформы AMD64. Случай довольно экзотический, не правда ли? Вирус написан на ассемблере под AMD64 и довольно прост, скорее всего, это - первая "проба пера" одного из вирусописателей. Интересный факт - 64-битные Windows-системы на базе платформы IA64 от Intel не подвержены риску - такая вот специфическая ситуация. Видимо поэтому, пока что зафиксировано лишь несколько десятков случаев заражения вирусом W64.Shruggle.1318...

При запуске, W64.Shruggle.1318 ищет 64-битные исполняемые файлы, при нахождении которых добавляет в них свой код (также инфицируются динамические библиотеки). Несмотря на то, что вирус безвреден для 32-разрядных платформ, он может быть запущен под окружением, симулирующим 64-битную среду. Внутри тела вируса найдена строчка "Shrug - roy g biv". Процедура заражения не отличается оригинальностью - последний раздел EXE-файла помечается как исполняемый, туда вставляется тело вируса, а в конец вирусной вставки добавляется несколько случайных байт информации. В очередной раз напоминаем вам о необходимости регулярной антивирусной проверки ваших систем...

© fcenter.ru 25.08.2004 15:16:00

W64.Shruggle.1318 is a direct-action file infector, similar to W64.Rugrat.3344, which infects AMD64 Windows Portable Executable (PE) files. It is a fairly simple proof-of-concept virus; however, it is the first known virus to attack 64-bit Windows executables on AMD64 systems.

The virus is written in AMD64 assembly code.




Type: Virus
Infection Length: 1318 bytes



Systems Affected: Windows 64-bit (AMD64)
Systems Not Affected: DOS, Linux, Macintosh, OS/2, UNIX, Windows 2000, Windows 3.x, Windows 64-bit (IA64), Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP






Virus Definitions (Intelligent Updater) *
August 21, 2004


Virus Definitions (LiveUpdate™) **
August 25, 2004


*
Intelligent Updater definitions are released daily, but require manual download and installation.
Click here to download manually.

**
LiveUpdate virus definitions are usually released every Wednesday.
Click here for instructions on using LiveUpdate.







Wild

Number of infections: 0 - 49
Number of sites: 0 - 2
Geographical distribution: Low
Threat containment: Easy
Removal: Easy
Threat Metrics


Wild:
Low
Damage:
Low
Distribution:
Low



Damage

Payload Trigger: n/a
Payload: n/a
Large scale e-mailing: n/a
Deletes files: n/a
Modifies files: Appends itself to 64-Bit .EXE files.
Degrades performance: n/a
Causes system instability: n/a
Releases confidential info: n/a
Compromises security settings: n/a
Distribution

Subject of email: n/a
Name of attachment: n/a
Size of attachment: n/a
Time stamp of attachment: n/a
Ports: n/a
Shared drives: n/a
Target of infection: n/a


When W64.Shruggle.1318 is executed, it searches 64-bit executable files that are in same folder, and all subfolders, as the one from which the virus was executed. When it finds a 64-bit executable file, the virus appends itself to the file, including .dll files.

Note: The virus does not infect 32-bit Portable Executable files, and it will not run natively on 32-bit Windows platforms. However, it can be run on a 32-bit computer that is using 64-bit simulation software.






Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.


Update the virus definitions.
Run a full system scan, and delete all of the files that are detected as W64.Shruggle.1318.

For specific details on each of these steps, read the following instructions.

1. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).

The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

2. To scan for and delete the infected files
Start your Symantec AntiVirus Enterprise product, and make sure that it is configured to scan all the files. For information, read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files."
Run a full system scan.
If any files are detected as being infected with W64.Shruggle.1318, click Delete.
Replace deleted files from a clean backup or reinstall them.


Additional information:

The virus uses a small number of Win64 APIs from the following three libraries:

Ntdll.dll
Sfc_os.dll
Kernel32.dll

From Ntdll.dll, the virus uses the following functions:
LdrGetDllHandle()
RtlAddVectoredExceptionHandler()
RtlRemoveVectoredExceptionHandler()

The virus supports vectored exception handling to avoid crashing during infections.

The SfcIsFileProtected() function of Sfc_os.dll is used to avoid infecting executables that are protected by the System File Checker (SFC).

The following sixteen functions are used from Kernel32.dll to implement a standard file infection of a AMD64 Portable Executable image:
CreateFileMappingA()
CreateFileW()
CloseHandle()
FindFirstFileW()
FindNextFileW
FindClose()
GetFullPathNameW()
GetTickCount()
GlobalAlloc()
GlobalFree()
LoadLibraryA()
MapViewOfFile()
SetCurrentDirectoryW()
SetFileAttributesW()
SetFileTime()
UnmapViewOfFile()

The virus carries the following string, which is never displayed, within itself:

Shrug - roy g biv

The file infection routine is standard. The last section of the executable is marked as executable, the virus body is inserted into the last section, and a random number of bytes are appended to the end of the virus body.

The virus author is also the author of a number of other proof-of-concept viruses. These are collected under the name W32.Chiton.gen.