Krilog

Overview

Spyware:Win32/Krilog (or Keylogger:Win32/Krilog) is a malicious tool designed specifically to capture a user's keystrokes (`T1056.001`), mouse clicks, and sometimes screen contents (`T1113`) without their knowledge or consent. It is a primary tool used by attackers for credential harvesting, corporate espionage, and identity theft.

Understanding Krilog (Keylogger)
To an end-user, a Krilog infection is entirely invisible; the software is designed specifically to hide its presence while silently recording activity. For a SOC analyst, a keylogger detection implies a total compromise of confidentiality for that host. Every password typed, every email drafted, and every secure portal accessed while the keylogger was active must be considered compromised.

Execution and Data Capture Mechanics
Krilog is typically dropped by a primary infection vector (like a trojan delivered via malspam). Once active, it uses low-level Windows APIs (such as `SetWindowsHookEx`) to intercept hardware events before they reach the intended application (`T1056.001`). It records these events into a hidden, encrypted log file (often stored in `%Temp%` or `%AppData%`). On a scheduled basis, Krilog bundles this log file and exfiltrates it to the attacker's C2 server (`T1041`), often via SMTP (email), FTP, or HTTP POST.

Indicators of Compromise & Impact
The impact is severe credential compromise and data theft. Host-based IoCs include EDR alerts for suspicious API hooking (e.g., a non-standard process injecting hooks into `explorer.exe` or browser processes). The presence of hidden, rapidly growing text or encrypted files in user profile directories is a strong indicator. Network IoCs involve regular, small bursts of outbound traffic (often SMTP or FTP) corresponding to the exfiltration of the keylog files.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1056.001: Implement Endpoint Detection and Response (EDR) to monitor for suspicious API calls related to keystroke interception. Enforce Multi-Factor Authentication (MFA) to render stolen passwords useless.

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_KRILOG {
    meta:
        description = "Detects Krilog (trojan)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "krilog" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Krilog Activity
id: d64bab2022c1c72b9e0b60c0d17860ba
status: experimental
description: Detects generic indicators of the krilog malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*krilog*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Isolate the endpoint immediately to prevent any further exfiltration of the captured keystrokes.
2. Assume all passwords typed on this machine since the estimated time of infection are compromised; force immediate password resets across all corporate accounts.
3. Analyze the exfiltrated log files (if they can be recovered locally) to determine exactly what sensitive data was stolen.
4. Use EDR or AV to identify and remove the Krilog executable and its associated registry persistence keys.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not allow the user to type their new passwords on the infected machine until it has been completely wiped and re-imaged.
2. Avoid closing the incident after removing the malware; the stolen credentials represent an ongoing threat.

References & External Analysis

• Search "krilog" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: trojan)

Explore other malware families in the same category:

• Phonerooter
• Gamania
• Hotkeyshook
• Plugx
• Commandcam

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/krilog.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.