Threat Database Trojans Trojan.MSIL.Krypt.ACAO

Trojan.MSIL.Krypt.ACAO

Threat Scorecard

Popularity Rank: 22,375
Threat Level: 80 % (High)
Infected Computers: 5
First Seen: February 23, 2023
Last Seen: October 17, 2026
OS(es) Affected: Windows

Trojan.MSIL.Krypt.ACAO is a Windows-based Trojan built on the Microsoft .NET framework that is designed to infiltrate systems quietly and carry out malicious instructions without the user's knowledge. With a danger level rated 8 out of 10, this threat has been active since early 2023 and continues to be detected on systems, making it a persistent concern for Windows users.

What Trojan.MSIL.Krypt.ACAO Does

Once active on a system, Trojan.MSIL.Krypt.ACAO operates silently in the background, avoiding obvious signs that would alert the user to its presence. It is compiled as a 64-bit .NET executable and is not digitally signed, which means it lacks the verification that legitimate software publishers typically provide. The Trojan has been observed creating and modifying files within hidden application data folders on the user's profile, including configuration and temporary files, suggesting it establishes a persistent presence and may store settings or data related to its operation.

This Trojan uses encryption-related system functions, which can indicate that it is designed to protect its own code, communications, or stolen data from being easily analyzed. It also checks for the presence of debugging tools, a technique commonly used by malware to detect when it is being examined by security researchers and to evade analysis. Beyond this, Trojan.MSIL.Krypt.ACAO may be capable of granting attackers remote access to the infected machine, potentially allowing them to delete files, install additional malicious programs, or manipulate the system in other harmful ways.

How It Usually Gets Onto Computers

Like many Trojans in its family, Trojan.MSIL.Krypt.ACAO typically spreads through deceptive means rather than exploiting a single specific vulnerability. Common infection methods include downloading software from untrustworthy or malicious websites, opening email attachments from unknown or unverified senders, and disguised files that may appear as executables, images, or other common formats to trick users into opening them. It can also take advantage of outdated software or unpatched security flaws on a system to install itself without obvious user interaction.

Risks for the User

Infections involving this type of Trojan carry serious risks. Because it can run silently and potentially provide attackers with control over the infected machine, users may face data theft, unauthorized file deletion, installation of additional malware, or complete compromise of system security. Personal information, login credentials, and other sensitive data stored or typed on the infected machine could be exposed to cybercriminals.

Signs of Infection

Because Trojans in this family are designed to operate covertly, visible symptoms are often minimal or absent. However, users might notice unusual system slowdowns, unexpected files appearing in application data folders, unfamiliar processes running in the background, or unexplained changes to system settings. Suspicious network activity, even when the system is otherwise idle, can also be a warning sign.

How to Stay Protected

To reduce the risk of infection, avoid downloading software from unofficial or questionable websites, and never open email attachments from unknown or unexpected senders. Keep the Windows operating system and all installed applications updated with the latest security patches to close known vulnerabilities. Exercise caution with any file that arrives unexpectedly, even if it appears to be a common format like an image or document, as disguised malicious files are a common infection tactic. Regularly backing up important data and using reputable, up-to-date security software can also help detect and remove threats like this one before they cause serious harm.

Analysis Report

General information

Family Name: Trojan.MSIL.Krypt.ACAO
Signature status: No Signature

Known Samples

MD5: a07e8390d2164892db9a5639d0557c38
SHA1: a60a0101f81e2063e6d44ab05f7fd713b4b13e2a
SHA256: 37B8700DA35755233CEFC6C4C607AF0B06472CA12B4E6B5ED42A00200A2E18A2
File Size: 922.62 KB, 922624 bytes

Windows Portable Executable Attributes

  • File doesn't have "Rich" header
  • File doesn't have exports table
  • File doesn't have relocations information
  • File doesn't have security information
  • File is .NET application
  • File is 64-bit executable
  • File is either console or GUI application
  • File is GUI application (IMAGE_SUBSYSTEM_WINDOWS_GUI)
  • File is not packed
  • IMAGE_FILE_DLL is not set inside PE header (Executable)
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  • IMAGE_FILE_EXECUTABLE_IMAGE is set inside PE header (Executable Image)

File Icons

Windows PE Version Information

Name Value
Assembly Version 2.0.3.0
File Description PT
File Version 2.0.3.0
Internal Name PT.exe
Legal Copyright Copyright © 2025
Original Filename PT.exe
Product Name PT
Product Version 2.0.3.0

File Traits

  • .NET
  • HighEntropy
  • x64

Block Information

Total Blocks: 666
Potentially Malicious Blocks: 17
Whitelisted Blocks: 277
Unknown Blocks: 372

Visual Map

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ? 0 0 ? ? 0 0 0 0 0 0 0 ? 0 ? ? ? 0 ? 0 0 0 0 0 0 0 ? ? ? ? ? ? 0 0 ? ? ? ? ? ? ? 0 0 x ? ? ? 0 0 ? 0 0 ? ? ? ? 0 ? ? 0 x 0 x 0 ? ? 0 0 ? ? ? ? 0 0 0 ? ? 0 ? ? ? ? ? ? ? ? ? ? ? ? ? 0 ? ? ? x ? 0 0 ? ? ? 0 0 0 0 ? 0 ? ? ? ? ? 0 ? ? ? ? ? ? ? ? 0 ? ? ? ? 0 0 ? ? ? ? 0 0 ? ? ? 0 0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0 ? 0 0 x ? ? ? 0 ? ? 0 0 ? ? ? ? ? ? ? ? ? ? ? 0 0 ? 0 0 ? ? ? ? ? ? 0 ? 0 0 0 ? ? ? 0 0 ? ? 0 0 0 0 0 0 ? ? ? ? ? ? ? 0 ? 0 ? ? ? ? 0 0 ? 0 ? ? ? x x ? ? ? ? 0 ? 0 ? 0 x 0 0 ? ? ? ? ? ? ? ? ? ? ? ? 0 0 0 x 0 0 0 ? ? ? 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ? ? ? 0 0 ? ? 0 0 0 0 ? 0 0 0 ? ? 0 ? 0 0 0 ? ? ? ? ? 0 ? 0 0 0 0 ? ? ? 0 0 0 0 0 0 ? 0 ? ? 0 0 ? 0 ? ? 0 ? x 0 0 0 0 ? ? ? ? ? ? 0 ? 0 ? 0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0 ? ? ? ? ? ? 0 ? ? ? ? ? ? ? ? 0 0 ? ? ? ? ? ? ? 0 ? ? ? ? ? 0 0 x x ? ? x ? ? ? ? 0 0 0 ? ? 0 ? ? ? 0 ? ? 0 ? 0 0 ? 0 ? ? ? ? ? 0 ? ? ? ? 0 ? ? ? ? ? 0 ? x x ? ? ? ? ? ? 0 ? ? ? 0 0 ? ? ? ? ? ? ? 0 0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0 ? ? ? 0 0 ? ? 0 0 0 0 0 0 0 0 0 ? ? 0 0 ? 0 ? 0 ? 0 0 0 0 0 ? 0 0 0 0 0 0 ? 0 0 0 ? 0 0 ? ? ? ? ? ? ? ? ? 0 0 0 ? ? ? ? ? ? 0 ? 0 ? ? ? ? x 0 0 0 0 0 0 ? 0 0 ? 0 0 ? 0 0 0 0 0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0 0 0 ? 0 0 ? ? ? x ? ? ? ? ? ? ?
0 - Probable Safe Block
? - Unknown Block
x - Potentially Malicious Block

Files Modified

File Attributes
c:\users\user\appdata\local\loginapp\a60a0101f81e2063e6d44ab05_url_ozjmkllw3upp10tpnjmsewmiqq1bktfa\2.0.3.0\4u3f3rfx.newcfg Generic Write,Read Attributes
c:\users\user\appdata\local\loginapp\a60a0101f81e2063e6d44ab05_url_ozjmkllw3upp10tpnjmsewmiqq1bktfa\2.0.3.0\4u3f3rfx.tmp Generic Write,Read Attributes
c:\users\user\appdata\local\loginapp\a60a0101f81e2063e6d44ab05_url_ozjmkllw3upp10tpnjmsewmiqq1bktfa\2.0.3.0\user.config Synchronize,Write Data

Registry Modifications

Key::Value Data API Name
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::proxybypass  RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::intranetname  RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::uncasintranet  RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::autodetect RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::proxybypass  RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::intranetname  RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::uncasintranet  RegNtPreCreateKey
HKCU\software\microsoft\windows\currentversion\internet settings\zonemap::autodetect RegNtPreCreateKey

Windows API Usage

Category API
Syscall Use
  • ntdll.dll!NtAlpcConnectPort
  • ntdll.dll!NtAlpcConnectPortEx
  • ntdll.dll!NtAlpcQueryInformation
  • ntdll.dll!NtAlpcSendWaitReceivePort
  • ntdll.dll!NtApphelpCacheControl
  • ntdll.dll!NtAssociateWaitCompletionPacket
  • ntdll.dll!NtClearEvent
  • ntdll.dll!NtClose
  • ntdll.dll!NtConnectPort
  • ntdll.dll!NtCreateEvent
Show More
  • ntdll.dll!NtCreateIoCompletion
  • ntdll.dll!NtCreateKey
  • ntdll.dll!NtCreateMutant
  • ntdll.dll!NtCreatePrivateNamespace
  • ntdll.dll!NtCreateSection
  • ntdll.dll!NtCreateSemaphore
  • ntdll.dll!NtCreateThreadEx
  • ntdll.dll!NtCreateTimer2
  • ntdll.dll!NtCreateWaitCompletionPacket
  • ntdll.dll!NtCreateWorkerFactory
  • ntdll.dll!NtDeviceIoControlFile
  • ntdll.dll!NtDuplicateObject
  • ntdll.dll!NtEnumerateKey
  • ntdll.dll!NtEnumerateValueKey
  • ntdll.dll!NtFreeVirtualMemory
  • ntdll.dll!NtFsControlFile
  • ntdll.dll!NtMapViewOfSection
  • ntdll.dll!NtOpenDirectoryObject
  • ntdll.dll!NtOpenEvent
  • ntdll.dll!NtOpenFile
  • ntdll.dll!NtOpenKey
  • ntdll.dll!NtOpenKeyEx
  • ntdll.dll!NtOpenProcess
  • ntdll.dll!NtOpenProcessToken
  • ntdll.dll!NtOpenSection
  • ntdll.dll!NtOpenSemaphore
  • ntdll.dll!NtOpenSymbolicLinkObject
  • ntdll.dll!NtOpenThreadToken
  • ntdll.dll!NtPowerInformation
  • ntdll.dll!NtProtectVirtualMemory
  • ntdll.dll!NtQueryAttributesFile
  • ntdll.dll!NtQueryDefaultLocale
  • ntdll.dll!NtQueryDirectoryFileEx
  • ntdll.dll!NtQueryEvent
  • ntdll.dll!NtQueryFullAttributesFile
  • ntdll.dll!NtQueryInformationFile
  • ntdll.dll!NtQueryInformationJobObject
  • ntdll.dll!NtQueryInformationProcess
  • ntdll.dll!NtQueryInformationThread
  • ntdll.dll!NtQueryInformationToken
  • ntdll.dll!NtQueryKey
  • ntdll.dll!NtQueryLicenseValue
  • ntdll.dll!NtQueryPerformanceCounter
  • ntdll.dll!NtQuerySecurityAttributesToken
  • ntdll.dll!NtQuerySecurityObject
  • ntdll.dll!NtQuerySystemInformation
  • ntdll.dll!NtQuerySystemInformationEx
  • ntdll.dll!NtQueryValueKey
  • ntdll.dll!NtQueryVirtualMemory
  • ntdll.dll!NtQueryVolumeInformationFile
  • ntdll.dll!NtQueryWnfStateData
  • ntdll.dll!NtReadFile
  • ntdll.dll!NtReadRequestData
  • ntdll.dll!NtReleaseMutant
  • ntdll.dll!NtReleaseSemaphore
  • ntdll.dll!NtReleaseWorkerFactoryWorker
  • ntdll.dll!NtRequestWaitReplyPort
  • ntdll.dll!NtResumeThread
  • ntdll.dll!NtSetEvent
  • ntdll.dll!NtSetInformationKey
  • ntdll.dll!NtSetInformationProcess
  • ntdll.dll!NtSetInformationThread
  • ntdll.dll!NtSetInformationVirtualMemory
  • ntdll.dll!NtSetInformationWorkerFactory
  • ntdll.dll!NtSetSecurityObject
  • ntdll.dll!NtSetTimer2
  • ntdll.dll!NtSubscribeWnfStateChange
  • ntdll.dll!NtTestAlert
  • ntdll.dll!NtTraceControl
  • ntdll.dll!NtUnmapViewOfSection
  • ntdll.dll!NtUnmapViewOfSectionEx
  • ntdll.dll!NtWaitForSingleObject
  • ntdll.dll!NtWaitForWorkViaWorkerFactory
  • ntdll.dll!NtWaitLowEventPair
  • ntdll.dll!NtWorkerFactoryWorkerReady
  • ntdll.dll!NtWriteFile
  • ntdll.dll!NtYieldExecution
  • UNKNOWN
User Data Access
  • GetComputerNameEx
  • GetUserDefaultLocaleName
  • GetUserObjectInformation
Encryption Used
  • BCryptOpenAlgorithmProvider
Anti Debug
  • IsDebuggerPresent