{
	"id": "a6adea22-b56a-40b1-90e1-9b17b5eded25",
	"created_at": "2026-04-06T00:11:03.622042Z",
	"updated_at": "2026-04-10T13:12:33.68937Z",
	"deleted_at": null,
	"sha1_hash": "9b62eb11161477b4566dfd6b4d4871748dadee7a",
	"title": "PE_MOFKSYS.A - Threat Encyclopedia | Trend Micro (US)",
	"llm_title": "",
	"authors": "",
	"file_creation_date": "0001-01-01T00:00:00Z",
	"file_modification_date": "0001-01-01T00:00:00Z",
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	"plain_text": "PE_MOFKSYS.A - Threat Encyclopedia | Trend Micro (US)\r\nBy Modified by: Sabrina Lei Sioting\r\nArchived: 2026-04-05 23:20:30 UTC\r\nThis file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by\r\nusers when visiting malicious sites.\r\nIt uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.\r\nIt modifies registry entries to disable various system services. This action prevents most of the system functions to\r\nbe used.\r\nIt prepends its codes to target files.\r\nIt executes commands from a remote malicious user, effectively compromising the affected system.\r\nIt steals certain information from the system and/or the user.\r\nArrival Details\r\nThis file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by\r\nusers when visiting malicious sites.\r\nInstallation\r\nThis file infector drops the following non-malicious files:\r\n%System%\\cmsys.cmn\r\n%User Profile%\\Application Data\\icsys.icn\r\n(Note: %System% is the Windows system folder, which is usually C:\\Windows\\System32.. %User Profile% is the\r\ncurrent user's profile folder, which is usually C:\\Documents and Settings\\{user name} on Windows 2000, XP, and\r\nServer 2003, or C:\\Users\\{user name} on Windows Vista and 7.)\r\nIt uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.\r\nAutostart Technique\r\nThis file infector adds the following registry entries to enable its automatic execution at every system startup:\r\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nWindows\\CurrentVersion\\RunOnce\r\nSvchost = \"%Windows%\\svchost.exe RO\"\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 1 of 7\n\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nActive Setup\\Installed Components\\{Random CLSID}\r\nStubPath = \"%Application Data%\\mrsys.exe MR\"\r\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nWindows\\CurrentVersion\\RunOnce\r\nExplorer = \"%System%\\explorer.exe RO\"\r\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nWindows\\CurrentVersion\\Run\r\nExplorer = \"%System%\\explorer.exe RU\"\r\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nWindows\\CurrentVersion\\Run\r\nSvchost = \"%Windows%\\svchost.exe RU\"\r\nIt modifies the following registry entries to ensure it automatic execution at every system startup:\r\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nWindows NT\\CurrentVersion\\Winlogon\r\nShell = \"%Windows%\\explorer.exe, %System%\\explorer.exe\"\r\n(Note: The default value data of the said registry entry is Explorer.exe.)\r\nThe scheduled task executes the malware at the following period:\r\nEveryday at malware's first execution time\r\nOther System Modifications\r\nThis file infector adds the following registry entries as part of its installation routine:\r\nHKEY_CURRENT_USER\\Software\\VB and VBA Program Settings\\\r\nExplorer\\Process\r\nLO = \"1\"\r\nHKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\\r\nServices\\Schedule\r\nAtTaskMaxHours = \"48\"\r\nIt adds the following registry keys as part of its installation routine:\r\nHKEY_CURRENT_USER\\Software\\VB and VBA Program Settings\r\nHKEY_CURRENT_USER\\Software\\VB and VBA Program Settings\\\r\nExplorer\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 2 of 7\n\nHKEY_CURRENT_USER\\Software\\VB and VBA Program Settings\\\r\nExplorer\\Process\r\nHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\\r\nActive Setup\\Installed Components\\{Random CLSID}\r\nIt modifies registry entries to disable the following system services:\r\nHKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\\r\nServices\\SharedAccess\r\nStart = \"4\"\r\n(Note: The default value data of the said registry entry is 2.)\r\nIt modifies the following registry entries to hide files with Hidden attributes:\r\nHKEY_CURRENT_USER\\Software\\Microsoft\\\r\nWindows\\CurrentVersion\\Explorer\\\r\nAdvanced\r\nShowSuperHidden = \"0\"\r\n(Note: The default value data of the said registry entry is 1.)\r\nFile Infection\r\nThis file infector infects the following file types:\r\n.EXE\r\nIt prepends its codes to target files.\r\nThis is the Trend Micro detection for files infected by:\r\nPE_MOFKSYS.A-O\r\nBackdoor Routine\r\nThis file infector executes the following commands from a remote malicious user:\r\nUpdate itself\r\nDownload other files\r\nCapture screen\r\nLog Keystrokes\r\nMonitor mouse clicks\r\nMonitor window titles\r\nIt connects to the following URL(s) to send and receive commands from a remote malicious user:\r\n{BLOCKED}.t35.com\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 3 of 7\n\n{BLOCKED}.atspace.com\r\n{BLOCKED}.zxq.net\r\nDropping Routine\r\nThis file infector drops the following files:\r\n%Application Data%\\mrsys.exe - detected as PE_MOFKSYS.A-O\r\n%Windows%\\spoolsv.exe - detected as PE_MOFKSYS.A-O\r\n%Windows%\\svchost.exe - detected as PE_MOFKSYS.A-O\r\n%System%\\explorer.exe - detected as PE_MOFKSYS.A-O\r\n%User Profile%\\Application Data\\icsys.icn.exe - detected as PE_MOFKSYS.A-O\r\n%System Root%\\Documents and Settings\\All Users\\Application Data\\stsys.exe - detected as\r\nPE_MOFKSYS.A-O\r\n(Note: %Application Data% is the current user's Application Data folder, which is usually C:\\Documents and\r\nSettings\\{user name}\\Application Data on Windows 2000, XP, and Server 2003, or C:\\Users\\{user\r\nname}\\AppData\\Roaming on Windows Vista and 7.. %Windows% is the Windows folder, which is usually\r\nC:\\Windows.. %System% is the Windows system folder, which is usually C:\\Windows\\System32.. %User\r\nProfile% is the current user's profile folder, which is usually C:\\Documents and Settings\\{user name} on Windows\r\n2000, XP, and Server 2003, or C:\\Users\\{user name} on Windows Vista and 7.. %System Root% is the root folder,\r\nwhich is usually C:\\. It is also where the operating system is located.)\r\nInformation Theft\r\nThis file infector steals the following information:\r\nEmail configurations\r\n- User name\r\n- Password\r\n- Authenticate status\r\n- Use of SSL\r\n- SMTP server\r\n- SMTP port\r\n- recipients\r\nInstant messenger credentials\r\nWebsites visited\r\nClipboard contents\r\nDrop Points\r\nThis file infector uses its own SMTP engine to send the stolen data using the following domain server:\r\n{BLOCKED}1@gmail.com\r\n{BLOCKED}1@gmail.com\r\n{BLOCKED}2@gmail.com\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 4 of 7\n\n{BLOCKED}2@gmail.com\r\n{BLOCKED}6@gmail.com\r\nNOTES:\r\nIt infects all .EXE files inside the folders that was accessed by the user in all physical and removable drives.\r\nIt also shares the following folder in the network:\r\n%System Root%\\Documents and Settings\\All User\\Application Data\r\nStep 2\r\nRemove the malware/grayware file that dropped/downloaded PE_MOFKSYS.A\r\nPE_MOFKSYS.A-O\r\nStep 3\r\nIdentify and delete files detected as PE_MOFKSYS.A using the Recovery Console\r\n[ Learn More ]\r\nStep 4\r\nDelete this registry key\r\n[ Learn More ]\r\nImportant: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this\r\nstep only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft\r\narticleopen on a new tab first before modifying your computer's registry. Before you could do this, you must\r\nrestart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires\r\nyou to restart in safe mode, you may proceed to edit the system registry.\r\nIn HKEY_CURRENT_USER\\Software\r\nVB and VBA Program Settings\r\nStep 5\r\nDelete the random registry key/s that this malware created\r\n[ Learn More ]\r\nImportant: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this\r\nonly if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft\r\narticle first before modifying your computer's registry.\r\nStep 6\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 5 of 7\n\nDelete this registry value\r\n[ Learn More ]\r\nImportant: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this\r\nstep only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft\r\narticleopen on a new tab first before modifying your computer's registry.\r\nIn HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\RunOnce\r\nExplorer = \"%System%\\explorer.exe RO\"\r\nIn HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\RunOnce\r\nSvchost = \"%Windows%\\svchost.exe RO\"\r\nIn HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\r\nExplorer = \"%System%\\explorer.exe RU\"\r\nIn HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\r\nSvchost = \"%Windows%\\svchost.exe RU\"\r\nIn HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Schedule\r\nAtTaskMaxHours = \"48\"\r\nStep 7\r\nRestore this modified registry value\r\n[ Learn More ]\r\nImportant: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this\r\nstep only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft\r\narticleopen on a new tab first before modifying your computer's registry.\r\nIn HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon\r\nFrom: Shell = \"%Windows%\\explorer.exe, %System%\\explorer.exe\"\r\nTo: Shell = Explorer.exe\r\nIn HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\r\nFrom: Start = \"4\"\r\nTo: Start = 2\r\nIn HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced\r\nFrom: ShowSuperHidden = \"0\"\r\nTo: ShowSuperHidden = 1\r\nStep 8\r\nScan your computer with your Trend Micro product to clean files detected as PE_MOFKSYS.A. If the detected\r\nfiles have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required.\r\nYou may opt to simply delete the quarantined files. Please check this Knowledge Base pageopen on a new tab for\r\nmore information.\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 6 of 7\n\nDid this description help? Tell us how we did.open on a new tab\r\nSource: https://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nhttps://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/\r\nPage 7 of 7",
	"extraction_quality": 1,
	"language": "EN",
	"sources": [
		"Malpedia"
	],
	"origins": [
		"web"
	],
	"references": [
		"https://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/PE_MOFKSYS.A/"
	],
	"report_names": [
		"PE_MOFKSYS.A"
	],
	"threat_actors": [],
	"ts_created_at": 1775434263,
	"ts_updated_at": 1775826753,
	"ts_creation_date": 0,
	"ts_modification_date": 0,
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