Joe Sandbox Cloud Basic Analysis Report

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Windows Analysis Report
xcYJfxDKL0Sk.exe

Overview

General Information

Sample Name:xcYJfxDKL0Sk.exe
Analysis ID:1345576
MD5:a75658c26b3c3ef739148060446b8d9b
SHA1:d8ca42c0a901edea00fedce2d306e8e09bf27c91
SHA256:3a2bc0787d73f2e92b71865154496cef6c1a983c4137f16c3733c1663295fc43
Tags:exeRemcos
Infos:

Detection

Remcos
Score:100
Range:0 - 100
Whitelisted:false
Confidence:100%

Signatures

Found malware configuration
Yara detected UAC Bypass using CMSTP
Contains functionality to bypass UAC (CMSTPLUA)
Multi AV Scanner detection for submitted file
Malicious sample detected (through community Yara rule)
Yara detected Remcos RAT
Sigma detected: Remcos
Antivirus / Scanner detection for submitted sample
Antivirus detection for URL or domain
Multi AV Scanner detection for domain / URL
Connects to many ports of the same IP (likely port scanning)
Contains functionality to steal Firefox passwords or cookies
Delayed program exit found
Contains functionality to register a low level keyboard hook
Machine Learning detection for sample
Contains functionality to modify clipboard data
Contains functionality to steal Chrome passwords or cookies
Contains functionalty to change the wallpaper
Deletes itself after installation
C2 URLs / IPs found in malware configuration
Uses 32bit PE files
Yara signature match
Contains functionality to enumerate process and check for explorer.exe or svchost.exe (often used for thread injection)
Contains functionality to check if a debugger is running (IsDebuggerPresent)
Contains functionality to query locales information (e.g. system language)
Contains functionality to shutdown / reboot the system
Uses code obfuscation techniques (call, push, ret)
Internet Provider seen in connection with other malware
Detected potential crypto function
Contains functionality to query CPU information (cpuid)
Found potential string decryption / allocating functions
Contains functionality to call native functions
Contains functionality to launch a control a shell (cmd.exe)
Contains functionality to enumerate running services
Contains functionality to dynamically determine API calls
Contains functionality to read the clipboard data
HTTP GET or POST without a user agent
Contains functionality which may be used to detect a debugger (GetProcessHeap)
IP address seen in connection with other malware
Sample file is different than original file name gathered from version info
Extensive use of GetProcAddress (often used to hide API calls)
Contains functionality to read the PEB
Detected TCP or UDP traffic on non-standard ports
Contains functionality to download and launch executables
Contains functionality to retrieve information about pressed keystrokes
Uses Microsoft's Enhanced Cryptographic Provider
Creates a process in suspended mode (likely to inject code)
Contains functionality to simulate mouse events
Found WSH timer for Javascript or VBS script (likely evasive script)
Contains functionality for read data from the clipboard

Classification

Process Tree

  • System is w10x64
  • xcYJfxDKL0Sk.exe (PID: 6188 cmdline: C:\Users\user\Desktop\xcYJfxDKL0Sk.exe MD5: A75658C26B3C3EF739148060446B8D9B)
    • wscript.exe (PID: 6628 cmdline: "C:\Windows\System32\WScript.exe" "C:\Users\user\AppData\Local\Temp\frjghkytrkcmwefakksrc.vbs" MD5: FF00E0480075B095948000BDC66E81F0)
  • cleanup

Malware Threat Intel

Provided by

NameDescriptionAttributionBlogpost URLsLink
Remcos, RemcosRATRemcos (acronym of Remote Control & Surveillance Software) is a commercial Remote Access Tool to remotely control computers.Remcos is advertised as legitimate software which can be used for surveillance and penetration testing purposes, but has been used in numerous hacking campaigns.Remcos, once installed, opens a backdoor on the computer, granting full access to the remote user.Remcos is developed by the cybersecurity company BreakingSecurity.
  • APT33
  • The Gorgon Group
https://malpedia.caad.fkie.fraunhofer.de/details/win.remcos

Malware Configuration

Threatname: Remcos

{"Version": "4.9.2 Pro", "Host:Port:Password": "0.tcp.sa.ngrok.io:14096:1", "Assigned name": "RemoteHost (em ingls)", "Connect interval": "1", "Install flag": "Disable", "Setup HKCU\\Run": "Enable", "Setup HKLM\\Run": "Enable", "Install path": "Application path", "Copy file": "remcos.exe", "Startup value": "Disable", "Hide file": "Disable", "Mutex": "Rmc-7QVKVR", "Keylog flag": "0", "Keylog path": "Application path", "Keylog file": "logs.dat", "Keylog crypt": "Disable", "Hide keylog file": "Disable", "Screenshot flag": "Disable", "Screenshot time": "10", "Take Screenshot option": "Disable", "Take screenshot title": "", "Take screenshot time": "5", "Screenshot path": "AppData", "Screenshot file": "Capturas de tela", "Screenshot crypt": "Disable", "Mouse option": "Disable", "Delete file": "Disable", "Audio record time": "5"}

Yara Signatures

Initial Sample

SourceRuleDescriptionAuthorStrings
xcYJfxDKL0Sk.exeJoeSecurity_RemcosYara detected Remcos RATJoe Security
    xcYJfxDKL0Sk.exeJoeSecurity_UACBypassusingCMSTPYara detected UAC Bypass using CMSTPJoe Security
      xcYJfxDKL0Sk.exeWindows_Trojan_Remcos_b296e965unknownunknown
      • 0x6aaa8:$a1: Remcos restarted by watchdog!
      • 0x6b020:$a3: %02i:%02i:%02i:%03i
      xcYJfxDKL0Sk.exeREMCOS_RAT_variantsunknownunknown
      • 0x64afc:$str_a1: C:\Windows\System32\cmd.exe
      • 0x64a78:$str_a3: /k %windir%\System32\reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWOR
      • 0x64a78:$str_a4: /k %windir%\System32\reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWOR
      • 0x64f78:$str_a5: \AppData\Local\Google\Chrome\User Data\Default\Login Data
      • 0x657a8:$str_b1: CreateObject("Scripting.FileSystemObject").DeleteFile(Wscript.ScriptFullName)
      • 0x64b6c:$str_b2: Executing file:
      • 0x65bec:$str_b3: GetDirectListeningPort
      • 0x65598:$str_b4: Set fso = CreateObject("Scripting.FileSystemObject")
      • 0x65718:$str_b7: \update.vbs
      • 0x64b94:$str_b9: Downloaded file:
      • 0x64b80:$str_b10: Downloading file:
      • 0x64c24:$str_b12: Failed to upload file:
      • 0x65bb4:$str_b13: StartForward
      • 0x65bd4:$str_b14: StopForward
      • 0x65670:$str_b15: fso.DeleteFile "
      • 0x65604:$str_b16: On Error Resume Next
      • 0x656a0:$str_b17: fso.DeleteFolder "
      • 0x64c14:$str_b18: Uploaded file:
      • 0x64bd4:$str_b19: Unable to delete:
      • 0x65638:$str_b20: while fso.FileExists("
      • 0x650b1:$str_c0: [Firefox StoredLogins not found]
      xcYJfxDKL0Sk.exeINDICATOR_SUSPICIOUS_EXE_UACBypass_CMSTPCOMDetects Windows exceutables bypassing UAC using CMSTP COM interfaces. MITRE (T1218.003)ditekSHen
      • 0x649e8:$guid1: {3E5FC7F9-9A51-4367-9063-A120244FBEC7}
      • 0x6497c:$s1: CoGetObject
      • 0x64990:$s1: CoGetObject
      • 0x649ac:$s1: CoGetObject
      • 0x6e938:$s1: CoGetObject
      • 0x6493c:$s2: Elevation:Administrator!new:

      Memory Dumps

      SourceRuleDescriptionAuthorStrings
      00000000.00000000.1630897285.0000000000459000.00000002.00000001.01000000.00000003.sdmpJoeSecurity_RemcosYara detected Remcos RATJoe Security
        00000000.00000000.1630897285.0000000000459000.00000002.00000001.01000000.00000003.sdmpJoeSecurity_UACBypassusingCMSTPYara detected UAC Bypass using CMSTPJoe Security
          00000000.00000000.1630897285.0000000000459000.00000002.00000001.01000000.00000003.sdmpWindows_Trojan_Remcos_b296e965unknownunknown
          • 0x134a8:$a1: Remcos restarted by watchdog!
          • 0x13a20:$a3: %02i:%02i:%02i:%03i
          00000000.00000002.1752772463.0000000000459000.00000002.00000001.01000000.00000003.sdmpJoeSecurity_RemcosYara detected Remcos RATJoe Security
            00000000.00000002.1752772463.0000000000459000.00000002.00000001.01000000.00000003.sdmpJoeSecurity_UACBypassusingCMSTPYara detected UAC Bypass using CMSTPJoe Security
              Click to see the 4 entries

              Unpacked PEs

              SourceRuleDescriptionAuthorStrings
              0.0.xcYJfxDKL0Sk.exe.400000.0.unpackJoeSecurity_RemcosYara detected Remcos RATJoe Security
                0.0.xcYJfxDKL0Sk.exe.400000.0.unpackJoeSecurity_UACBypassusingCMSTPYara detected UAC Bypass using CMSTPJoe Security
                  0.0.xcYJfxDKL0Sk.exe.400000.0.unpackWindows_Trojan_Remcos_b296e965unknownunknown
                  • 0x6aaa8:$a1: Remcos restarted by watchdog!
                  • 0x6b020:$a3: %02i:%02i:%02i:%03i
                  0.0.xcYJfxDKL0Sk.exe.400000.0.unpackREMCOS_RAT_variantsunknownunknown
                  • 0x64afc:$str_a1: C:\Windows\System32\cmd.exe
                  • 0x64a78:$str_a3: /k %windir%\System32\reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWOR
                  • 0x64a78:$str_a4: /k %windir%\System32\reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWOR
                  • 0x64f78:$str_a5: \AppData\Local\Google\Chrome\User Data\Default\Login Data
                  • 0x657a8:$str_b1: CreateObject("Scripting.FileSystemObject").DeleteFile(Wscript.ScriptFullName)
                  • 0x64b6c:$str_b2: Executing file:
                  • 0x65bec:$str_b3: GetDirectListeningPort
                  • 0x65598:$str_b4: Set fso = CreateObject("Scripting.FileSystemObject")
                  • 0x65718:$str_b7: \update.vbs
                  • 0x64b94:$str_b9: Downloaded file:
                  • 0x64b80:$str_b10: Downloading file:
                  • 0x64c24:$str_b12: Failed to upload file:
                  • 0x65bb4:$str_b13: StartForward
                  • 0x65bd4:$str_b14: StopForward
                  • 0x65670:$str_b15: fso.DeleteFile "
                  • 0x65604:$str_b16: On Error Resume Next
                  • 0x656a0:$str_b17: fso.DeleteFolder "
                  • 0x64c14:$str_b18: Uploaded file:
                  • 0x64bd4:$str_b19: Unable to delete:
                  • 0x65638:$str_b20: while fso.FileExists("
                  • 0x650b1:$str_c0: [Firefox StoredLogins not found]
                  0.0.xcYJfxDKL0Sk.exe.400000.0.unpackINDICATOR_SUSPICIOUS_EXE_UACBypass_CMSTPCOMDetects Windows exceutables bypassing UAC using CMSTP COM interfaces. MITRE (T1218.003)ditekSHen
                  • 0x649e8:$guid1: {3E5FC7F9-9A51-4367-9063-A120244FBEC7}
                  • 0x6497c:$s1: CoGetObject
                  • 0x64990:$s1: CoGetObject
                  • 0x649ac:$s1: CoGetObject
                  • 0x6e938:$s1: CoGetObject
                  • 0x6493c:$s2: Elevation:Administrator!new:
                  Click to see the 5 entries

                  Sigma Signatures

                  Stealing of Sensitive Information

                  barindex
                  Sigma detected: Remcos
                  Source: Registry Key setAuthor: Joe Security: Data: Details: 53 9B A0 3B 8B E3 55 2E 28 47 F2 9A 07 38 83 FC D8 F7 16 E9 3F 85 A9 0F 43 69 34 10 DD 45 72 5B 6D 91 8E D8 B4 FB 8E 8D 2A A1 76 F8 43 62 0A BF D5 02 99 71 9E 0A 1A 22 A0 B3 AD 2C C1 80 0A 66 27 6B 9E 7C 63 F6 FC 77 EA 92 A3 AD 2A E9 C7 8D , EventID: 13, EventType: SetValue, Image: C:\Users\user\Desktop\xcYJfxDKL0Sk.exe, ProcessId: 6188, TargetObject: HKEY_CURRENT_USER\SOFTWARE\Rmc-7QVKVR\exepath

                  Snort Signatures

                  ⊘No Snort rule has matched

                  Joe Sandbox Signatures

                  Click to jump to signature section

                  Show All Signature Results

                  AV Detection

                  barindex
                  Found malware configuration
                  Source: 0.2.xcYJfxDKL0Sk.exe.400000.0.unpackMalware Configuration Extractor: Remcos {"Version": "4.9.2 Pro", "Host:Port:Password": "0.tcp.sa.ngrok.io:14096:1", "Assigned name": "RemoteHost (em ingls)", "Connect interval": "1", "Install flag": "Disable", "Setup HKCU\\Run": "Enable", "Setup HKLM\\Run": "Enable", "Install path": "Application path", "Copy file": "remcos.exe", "Startup value": "Disable", "Hide file": "Disable", "Mutex": "Rmc-7QVKVR", "Keylog flag": "0", "Keylog path": "Application path", "Keylog file": "logs.dat", "Keylog crypt": "Disable", "Hide keylog file": "Disable", "Screenshot flag": "Disable", "Screenshot time": "10", "Take Screenshot option": "Disable", "Take screenshot title": "", "Take screenshot time": "5", "Screenshot path": "AppData", "Screenshot file": "Capturas de tela", "Screenshot crypt": "Disable", "Mouse option": "Disable", "Delete file": "Disable", "Audio record time": "5"}
                  Multi AV Scanner detection for submitted file
                  Source: xcYJfxDKL0Sk.exeVirustotal: Detection: 80%Perma Link
                  Yara detected Remcos RAT
                  Source: Yara matchFile source: xcYJfxDKL0Sk.exe, type: SAMPLE
                  Source: Yara matchFile source: 0.0.xcYJfxDKL0Sk.exe.400000.0.unpack, type: UNPACKEDPE
                  Source: Yara matchFile source: 0.2.xcYJfxDKL0Sk.exe.400000.0.unpack, type: UNPACKEDPE
                  Source: Yara matchFile source: 00000000.00000000.1630897285.0000000000459000.00000002.00000001.01000000.00000003.sdmp, type: MEMORY
                  Source: Yara matchFile source: 00000000.00000002.1752772463.0000000000459000.00000002.00000001.01000000.00000003.sdmp, type: MEMORY
                  Source: Yara matchFile source: Process Memory Space: xcYJfxDKL0Sk.exe PID: 6188, type: MEMORYSTR
                  Antivirus / Scanner detection for submitted sample
                  Source: xcYJfxDKL0Sk.exeAvira: detected
                  Antivirus detection for URL or domain
                  Source: http://geoplugin.net/json.gpURL Reputation: Label: phishing
                  Source: http://geoplugin.net/json.gpURL Reputation: Label: phishing
                  Source: http://geoplugin.net/json.gp/CURL Reputation: Label: phishing
                  Source: 0.tcp.sa.ngrok.ioAvira URL Cloud: Label: malware
                  Multi AV Scanner detection for domain / URL
                  Source: 0.tcp.sa.ngrok.ioVirustotal: Detection: 14%Perma Link
                  Source: 0.tcp.sa.ngrok.ioVirustotal: Detection: 14%Perma Link
                  Machine Learning detection for sample
                  Source: xcYJfxDKL0Sk.exeJoe Sandbox ML: detected
                  Source: C:\Users\user\Desktop\xcYJfxDKL0Sk.exeCode function: 0_2_00433785 CryptAcquireContextA,CryptGenRandom,CryptReleaseContext,0_2_00433785
                  Source: xcYJfxDKL0Sk.exe, 00000000.00000000.1630897285.0000000000459000.00000002.00000001.01000000.00000003.sdmpBinary or memory string: -----BEGIN PUBLIC KEY-----memstr_e80f468d-2

                  Exploits

                  bar