Kolabc

Overview

Backdoor:Win32/Kolabc is a variant of the highly sophisticated Kolab trojan, engineered to establish a covert backdoor on compromised endpoints, facilitating credential theft, data exfiltration, and the silent delivery of secondary payloads.

Understanding Kolabc
To the victim, Kolabc provides zero visual indicators of compromise. For threat intelligence analysts, Kolabc represents a severe, capable RAT (Remote Access Trojan) frequently utilized in targeted espionage and ransomware precursor operations. It is designed to bypass initial security controls, harvest comprehensive system intelligence, and maintain long-term, undetected access to the victim network.

Execution and Evasion Strategies
Kolabc is typically delivered via spearphishing campaigns containing weaponized Office documents or dropped as a secondary payload by advanced exploit kits. Upon execution, it utilizes intense packing, encryption, and dynamic API resolution to evade static antivirus signatures. It drops a randomized executable into the <code>%AppData% or %SystemRoot% directories. Persistence is achieved by creating a hidden scheduled task, modifying the Registry Run keys, or installing a malicious Windows Service. Kolabc frequently injects its core modules into legitimate system processes (like svchost.exe or explorer.exe) to mask its outbound network traffic.

Indicators of Compromise (IoCs)
Threat hunters should investigate EDR alerts for 'Suspicious Process Injection', 'Service Creation', or 'Anomalous Child Process Spawning'. Network logs will often reveal Kolabc reaching out to compromised domains using custom-encrypted HTTP/HTTPS traffic. The presence of unexpected, hidden scheduled tasks designed to execute randomly named binaries in the user's profile is a strong IoC. Memory analysis is absolutely crucial to extract the injected modules and identify the specific C2 infrastructure.

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.
• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

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_KOLABC {
    meta:
        description = "Detects Kolabc (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "kolabc" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Kolabc Activity
id: e73fd2508804cefd1dab91cf44f9b2db
status: experimental
description: Detects generic indicators of the kolabc malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*kolabc*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Instantly isolate the endpoint from the network to sever the attacker's interactive, remote-control session.
2. Capture a full forensic memory image of the machine to extract the decrypted Kolabc payload and its C2 configuration.
3. Audit the Windows Task Scheduler, Registry Run keys, and Windows Services to identify and remove the Kolabc persistence mechanisms.
4. Assume total endpoint compromise; perform a clean OS rebuild and force global password resets for all accounts that accessed the machine.

What to Avoid

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

1. Do not leave the machine connected to the network during triage; the attacker has live access and will likely destroy evidence or move laterally.
2. Avoid relying solely on static file deletion, as the injected processes will likely just recreate the dropped binaries.

References & External Analysis

• Search "kolabc" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Babar
• Pinkblocker
• Yuner
• Ransomheur
• Musclecar

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/kolabc.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.