| File name: | INSTRUCTIONLETTER63-2025.exe |
| Full analysis: | https://app.any.run/tasks/4f186e11-054f-4ecd-90fe-5329ef704068 |
| Verdict: | Malicious activity |
| Threats: | First identified in March 2021, PureCrypter is a .NET-based loader that employs obfuscation techniques, such as SmartAssembly, to evade detection. It has been used to distribute malware families including AgentTesla, RedLine Stealer, and SnakeKeylogger. The malware is typically delivered through phishing campaigns and malicious downloads, often masquerading as legitimate files with extensions like .mp4 or .pdf. PureCrypter utilizes encryption and compression to conceal its payloads and can inject malicious code into legitimate processes to maintain persistence on the infected system. |
| Analysis date: | March 25, 2025, 03:50:28 |
| OS: | Windows 10 Professional (build: 19045, 64 bit) |
| Tags: | |
| Indicators: | |
| MIME: | application/vnd.microsoft.portable-executable |
| File info: | PE32 executable (GUI) Intel 80386 Mono/.Net assembly, for MS Windows, 3 sections |
| MD5: | 1CE4EEC150B3F140F72CE0DDCAD39337 |
| SHA1: | E5FB09B22C4C04025281DA6661D7C895D7D496A9 |
| SHA256: | 2A64D3212309DA646F5EF8210F6B8966C7A63CE82CB5BBD3C03838DD296BADCF |
| SSDEEP: | 49152:95akkiigYtI295TAChHWvd8GXW8Q7c1qWrW43ggZmzlrRemteQvkuyWhc6d1S0Dt:95h5iNfTnhHGyL8Q7ZWrWeg4mz73tRk2 |
MALICIOUS
PURECRYPTER has been detected (YARA)
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
Create files in the Startup directory
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
Steals credentials from Web Browsers
- InstallUtil.exe (PID: 2908)
Actions looks like stealing of personal data
- InstallUtil.exe (PID: 2908)
SUSPICIOUS
Executable content was dropped or overwritten
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
Checks for external IP
- svchost.exe (PID: 2196)
- InstallUtil.exe (PID: 2908)
Connects to SMTP port
- InstallUtil.exe (PID: 2908)
Reads security settings of Internet Explorer
- ShellExperienceHost.exe (PID: 5360)
INFO
Autorun file from Startup directory
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
Reads the machine GUID from the registry
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
- InstallUtil.exe (PID: 2908)
Checks supported languages
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
- InstallUtil.exe (PID: 2908)
- ShellExperienceHost.exe (PID: 5360)
Reads the computer name
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
- InstallUtil.exe (PID: 2908)
- ShellExperienceHost.exe (PID: 5360)
Creates files or folders in the user directory
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
- BackgroundTransferHost.exe (PID: 2552)
Manual execution by a user
- InstallUtil.exe (PID: 2908)
.NET Reactor protector has been detected
- INSTRUCTIONLETTER63-2025.exe (PID: 3900)
Disables trace logs
- InstallUtil.exe (PID: 2908)
Checks proxy server information
- InstallUtil.exe (PID: 2908)
- BackgroundTransferHost.exe (PID: 2552)
ULTRAVNC has been detected
- InstallUtil.exe (PID: 2908)
Reads the software policy settings
- InstallUtil.exe (PID: 2908)
- BackgroundTransferHost.exe (PID: 2552)
- slui.exe (PID: 7084)
Reads security settings of Internet Explorer
- BackgroundTransferHost.exe (PID: 3140)
- BackgroundTransferHost.exe (PID: 2552)
- BackgroundTransferHost.exe (PID: 3140)
- BackgroundTransferHost.exe (PID: 1328)
- BackgroundTransferHost.exe (PID: 6240)
Find more information about signature artifacts and mapping to MITRE ATT&CK™ MATRIX at the full report
TRiD
| .exe | | | Generic CIL Executable (.NET, Mono, etc.) (56.7) |
|---|---|---|
| .exe | | | Win64 Executable (generic) (21.3) |
| .scr | | | Windows screen saver (10.1) |
| .dll | | | Win32 Dynamic Link Library (generic) (5) |
| .exe | | | Win32 Executable (generic) (3.4) |
EXIF
EXE
| MachineType: | Intel 386 or later, and compatibles |
|---|---|
| TimeStamp: | 2025:03:24 21:50:21+00:00 |
| ImageFileCharacteristics: | Executable, No line numbers, No symbols, 32-bit |
| PEType: | PE32 |
| LinkerVersion: | 8 |
| CodeSize: | 1315840 |
| InitializedDataSize: | 2048 |
| UninitializedDataSize: | - |
| EntryPoint: | 0x14329e |
| OSVersion: | 4 |
| ImageVersion: | - |
| SubsystemVersion: | 4 |
| Subsystem: | Windows GUI |
| FileVersionNumber: | 1.0.0.0 |
| ProductVersionNumber: | 1.0.0.0 |
| FileFlagsMask: | 0x003f |
| FileFlags: | (none) |
| FileOS: | Win32 |
| ObjectFileType: | Executable application |
| FileSubtype: | - |
| LanguageCode: | Neutral |
| CharacterSet: | Unicode |
| Comments: | - |
| CompanyName: | - |
| FileDescription: | Dlnfcrr |
| FileVersion: | 1.0.0.0 |
| InternalName: | Dlnfcrr.exe |
| LegalCopyright: | Copyright © 2016 |
| LegalTrademarks: | - |
| OriginalFileName: | Dlnfcrr.exe |
| ProductName: | Dlnfcrr |
| ProductVersion: | 1.0.0.0 |
| AssemblyVersion: | 1.0.0.0 |
Total processes
144
Monitored processes
12
Malicious processes
2
Suspicious processes
0
Behavior graph
Click at the process to see the details
Process information
PID | CMD | Path | Indicators | Parent process | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1328 | "BackgroundTransferHost.exe" -ServerName:BackgroundTransferHost.1 | C:\Windows\System32\BackgroundTransferHost.exe | — | svchost.exe | |||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: Download/Upload Host Exit code: 1 Version: 10.0.19041.3636 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 2196 | C:\WINDOWS\system32\svchost.exe -k NetworkService -p -s Dnscache | C:\Windows\System32\svchost.exe | services.exe | ||||||||||||
User: NETWORK SERVICE Company: Microsoft Corporation Integrity Level: SYSTEM Description: Host Process for Windows Services Version: 10.0.19041.1 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 2552 | "BackgroundTransferHost.exe" -ServerName:BackgroundTransferHost.1 | C:\Windows\System32\BackgroundTransferHost.exe | svchost.exe | ||||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: Download/Upload Host Exit code: 1 Version: 10.0.19041.3636 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 2908 | "C:\Windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.exe" | C:\Windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.exe | explorer.exe | ||||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: .NET Framework installation utility Version: 4.8.9037.0 built by: NET481REL1 Modules
| |||||||||||||||
| 3140 | "BackgroundTransferHost.exe" -ServerName:BackgroundTransferHost.1 | C:\Windows\System32\BackgroundTransferHost.exe | — | svchost.exe | |||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: Download/Upload Host Exit code: 1 Version: 10.0.19041.3636 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 3140 | "BackgroundTransferHost.exe" -ServerName:BackgroundTransferHost.1 | C:\Windows\System32\BackgroundTransferHost.exe | — | svchost.exe | |||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: Download/Upload Host Exit code: 1 Version: 10.0.19041.3636 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 3900 | "C:\Users\admin\Desktop\INSTRUCTIONLETTER63-2025.exe" | C:\Users\admin\Desktop\INSTRUCTIONLETTER63-2025.exe | explorer.exe | ||||||||||||
User: admin Integrity Level: MEDIUM Description: Dlnfcrr Exit code: 4294967295 Version: 1.0.0.0 Modules
| |||||||||||||||
| 4380 | C:\WINDOWS\system32\SppExtComObj.exe -Embedding | C:\Windows\System32\SppExtComObj.Exe | — | svchost.exe | |||||||||||
User: NETWORK SERVICE Company: Microsoft Corporation Integrity Level: SYSTEM Description: KMS Connection Broker Version: 10.0.19041.3996 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 4696 | C:\WINDOWS\System32\slui.exe -Embedding | C:\Windows\System32\slui.exe | — | svchost.exe | |||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: Windows Activation Client Version: 10.0.19041.1 (WinBuild.160101.0800) Modules
| |||||||||||||||
| 5360 | "C:\WINDOWS\SystemApps\ShellExperienceHost_cw5n1h2txyewy\ShellExperienceHost.exe" -ServerName:App.AppXtk181tbxbce2qsex02s8tw7hfxa9xb3t.mca | C:\Windows\SystemApps\ShellExperienceHost_cw5n1h2txyewy\ShellExperienceHost.exe | — | svchost.exe | |||||||||||
User: admin Company: Microsoft Corporation Integrity Level: MEDIUM Description: Windows Shell Experience Host Version: 10.0.19041.3758 (WinBuild.160101.0800) Modules
| |||||||||||||||
Total events
4 077
Read events
4 048
Write events
29
Delete events
0
Modification events
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | EnableFileTracing |
Value: 0 | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | EnableAutoFileTracing |
Value: 0 | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | EnableConsoleTracing |
Value: 0 | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | FileTracingMask |
Value: | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | ConsoleTracingMask |
Value: | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | MaxFileSize |
Value: 1048576 | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASAPI32 |
| Operation: | write | Name: | FileDirectory |
Value: %windir%\tracing | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASMANCS |
| Operation: | write | Name: | EnableFileTracing |
Value: 0 | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASMANCS |
| Operation: | write | Name: | EnableAutoFileTracing |
Value: 0 | |||
| (PID) Process: | (2908) InstallUtil.exe | Key: | HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Tracing\InstallUtil_RASMANCS |
| Operation: | write | Name: | EnableConsoleTracing |
Value: 0 | |||
Executable files
1
Suspicious files
5
Text files
1
Unknown types
0
Dropped files
PID | Process | Filename | Type | |
|---|---|---|---|---|
| 2552 | BackgroundTransferHost.exe | C:\Users\admin\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\AC\BackgroundTransferApi\5695b18f-0e78-4dbe-8d70-868181947f04.down_data | — | |
MD5:— | SHA256:— | |||
| 2552 | BackgroundTransferHost.exe | C:\Users\admin\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\AC\Microsoft\CryptnetUrlCache\Content\26C212D9399727259664BDFCA073966E_F9F7D6A7ECE73106D2A8C63168CDA10D | binary | |
MD5:4872BABAF39AA62B8D32695EBB7E9173 | SHA256:2EE85DF86EE29BBEB3DCA81AA29B6DE204F605A2769B84C728A329178A2D0999 | |||
| 2552 | BackgroundTransferHost.exe | C:\Users\admin\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\AC\BackgroundTransferApi\5695b18f-0e78-4dbe-8d70-868181947f04.a81739b9-a505-42b3-b110-c4728b31ffa1.down_meta | binary | |
MD5:E0565071A52824A05DC53893E13CCC77 | SHA256:8B565952F5F423619E38447F4C70EEDE9636DD1B758E1421084A37886133C453 | |||
| 3900 | INSTRUCTIONLETTER63-2025.exe | C:\Users\admin\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\Keywords.vbs | text | |
MD5:D360A32975E1150FEC5DB07597A19052 | SHA256:3BA68535BE0D4B591491DC7FC2D5F0040C5137946568AA33DE49F1772A215851 | |||
| 3900 | INSTRUCTIONLETTER63-2025.exe | C:\Users\admin\AppData\Roaming\Keywords.exe | executable | |
MD5:1CE4EEC150B3F140F72CE0DDCAD39337 | SHA256:2A64D3212309DA646F5EF8210F6B8966C7A63CE82CB5BBD3C03838DD296BADCF | |||
| 2552 | BackgroundTransferHost.exe | C:\Users\admin\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\AC\BackgroundTransferApi\6c9be1d9-7899-4256-b7d7-2a3d942c5705.up_meta_secure | binary | |
MD5:0DD145BD4C9021E20C9496DD91A6E8DA | SHA256:B331A2A634EB891EE0132EECBEEC51B2BCAAAF17D88215AA88FE5ACDD06F8C81 | |||
| 2552 | BackgroundTransferHost.exe | C:\Users\admin\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\AC\Microsoft\CryptnetUrlCache\MetaData\26C212D9399727259664BDFCA073966E_F9F7D6A7ECE73106D2A8C63168CDA10D | binary | |
MD5:FEB2B8840B2E055B73554E0E827F4D2D | SHA256:325D77E0BA783A12C917D570A1BDC2098F0319529ED8826EC3E7B666B8510FF1 | |||
| 2552 | BackgroundTransferHost.exe | C:\Users\admin\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\AC\BackgroundTransferApi\6c9be1d9-7899-4256-b7d7-2a3d942c5705.a81739b9-a505-42b3-b110-c4728b31ffa1.down_meta | binary | |
MD5:E0565071A52824A05DC53893E13CCC77 | SHA256:8B565952F5F423619E38447F4C70EEDE9636DD1B758E1421084A37886133C453 | |||
Download PCAP, analyze network streams, HTTP content and a lot more at the full report
HTTP(S) requests
8
TCP/UDP connections
33
DNS requests
26
Threats
2
HTTP requests
PID | Process | Method | HTTP Code | IP | URL | CN | Type | Size | Reputation |
|---|---|---|---|---|---|---|---|---|---|
6544 | svchost.exe | GET | 200 | 2.23.77.188:80 | http://ocsp.digicert.com/MFEwTzBNMEswSTAJBgUrDgMCGgUABBSAUQYBMq2awn1Rh6Doh%2FsBYgFV7gQUA95QNVbRTLtm8KPiGxvDl7I90VUCEAJ0LqoXyo4hxxe7H%2Fz9DKA%3D | unknown | — | — | whitelisted |
— | — | GET | 200 | 2.16.164.120:80 | http://crl.microsoft.com/pki/crl/products/MicRooCerAut2011_2011_03_22.crl | unknown | — | — | whitelisted |
5496 | MoUsoCoreWorker.exe | GET | 200 | 2.16.164.120:80 | http://crl.microsoft.com/pki/crl/products/MicRooCerAut2011_2011_03_22.crl | unknown | — | — | whitelisted |
2552 | BackgroundTransferHost.exe | GET | 200 | 2.23.77.188:80 | http://ocsp.digicert.com/MFEwTzBNMEswSTAJBgUrDgMCGgUABBTrjrydRyt%2BApF3GSPypfHBxR5XtQQUs9tIpPmhxdiuNkHMEWNpYim8S8YCEAI5PUjXAkJafLQcAAsO18o%3D | unknown | — | — | whitelisted |
5308 | backgroundTaskHost.exe | GET | 200 | 2.23.77.188:80 | http://ocsp.digicert.com/MFEwTzBNMEswSTAJBgUrDgMCGgUABBQ50otx%2Fh0Ztl%2Bz8SiPI7wEWVxDlQQUTiJUIBiV5uNu5g%2F6%2BrkS7QYXjzkCEAUZZSZEml49Gjh0j13P68w%3D | unknown | — | — | whitelisted |
5084 | SIHClient.exe | GET | 200 | 23.222.10.99:80 | http://www.microsoft.com/pkiops/crl/Microsoft%20ECC%20Product%20Root%20Certificate%20Authority%202018.crl | unknown | — | — | whitelisted |
5084 | SIHClient.exe | GET | 200 | 23.222.10.99:80 | http://www.microsoft.com/pkiops/crl/Microsoft%20ECC%20Update%20Secure%20Server%20CA%202.1.crl | unknown | — | — | whitelisted |
2924 | SearchApp.exe | GET | 200 | 2.17.190.73:80 | http://ocsp.digicert.com/MFEwTzBNMEswSTAJBgUrDgMCGgUABBQ50otx%2Fh0Ztl%2Bz8SiPI7wEWVxDlQQUTiJUIBiV5uNu5g%2F6%2BrkS7QYXjzkCEAn5bsKVVV8kdJ6vHl3O1J0%3D | unknown | — | — | whitelisted |
Download PCAP, analyze network streams, HTTP content and a lot more at the full report
Connections
PID | Process | IP | Domain | ASN | CN | Reputation |
|---|---|---|---|---|---|---|
4 | System | 192.168.100.255:137 | — | — | — | whitelisted |
— | — | 51.124.78.146:443 | settings-win.data.microsoft.com | MICROSOFT-CORP-MSN-AS-BLOCK | NL | whitelisted |
— | — | 2.16.164.120:80 | crl.microsoft.com | Akamai International B.V. | NL | whitelisted |
5496 | MoUsoCoreWorker.exe | 2.16.164.120:80 | crl.microsoft.com | Akamai International B.V. | NL | whitelisted |
4 | System | 192.168.100.255:138 | — | — | — | whitelisted |
3216 | svchost.exe | 40.113.110.67:443 | client.wns.windows.com | MICROSOFT-CORP-MSN-AS-BLOCK | NL | whitelisted |
6544 | svchost.exe | 40.126.32.133:443 | login.live.com | MICROSOFT-CORP-MSN-AS-BLOCK | NL | whitelisted |
6544 | svchost.exe | 2.23.77.188:80 | ocsp.digicert.com | AKAMAI-AS | DE | whitelisted |
2104 | svchost.exe | 4.231.128.59:443 | settings-win.data.microsoft.com | MICROSOFT-CORP-MSN-AS-BLOCK | IE | whitelisted |
5308 | backgroundTaskHost.exe | 20.223.35.26:443 | arc.msn.com | MICROSOFT-CORP-MSN-AS-BLOCK | IE | whitelisted |
DNS requests
Domain | IP | Reputation |
|---|---|---|
settings-win.data.microsoft.com |
| whitelisted |
google.com |
| whitelisted |
crl.microsoft.com |
| whitelisted |
client.wns.windows.com |
| whitelisted |
login.live.com |
| whitelisted |
ocsp.digicert.com |
| whitelisted |
arc.msn.com |
| whitelisted |
api.ipify.org |
| shared |
mail.iaa-airferight.com |
| malicious |
www.bing.com |
| whitelisted |
Threats
PID | Process | Class | Message |
|---|---|---|---|
2196 | svchost.exe | Misc activity | ET INFO External IP Lookup Domain (ipify .org) in DNS Lookup |
2908 | InstallUtil.exe | Misc activity | ET INFO External IP Address Lookup Domain (ipify .org) in TLS SNI |