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MITRE ATT&CK® Malware

S0187: Daserf

Daserf is a backdoor that has been used to spy on and steal from Japanese, South Korean, Russian, Singaporean, and Chinese victims. Researchers have identified versions written in both Visual C and Delphi. [1] [2]

EnterpriseS0187MalwareObject v1.1 Modified
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Glexia's Take

Analyst context for executives and security teams

Analyst confidence Medium

Daserf is a Windows backdoor associated in ATT&CK with espionage-focused activity and capabilities for credential theft, collection, command execution, tool transfer, and stealthy command-and-control. For leaders, the practical issue is not just the malware name; it is whether the organization can prove it would notice a Windows host behaving like a long-running remote access implant that hides traffic, captures user activity, and prepares data for theft.

Executive priority

Prioritize Daserf as a validation case for endpoint visibility, identity protection, and incident response readiness on Windows systems. The ATT&CK relationships tie it to LSASS memory access, keylogging, screen capture, archiving collected data, web-based C2, steganography, encoding, and symmetric cryptography. Executives should ask whether SOC evidence can connect these behaviors into an intrusion story, whether privileged credential exposure would be contained quickly, and whether audit/compliance evidence exists for monitoring sensitive Windows endpoints and outbound network activity.

Technical view

ATT&CK does not provide a Daserf-specific detection section, so defenders should validate behavior-based coverage from the related techniques rather than rely on a malware signature. On Windows, focus on unusual LSASS access, suspicious command shell execution, unexpected packed or obfuscated binaries, binaries placed or named to resemble legitimate resources, signed-but-untrusted or unusual executables, keylogging or screen capture indicators, archive creation around sensitive data, ingress tool transfer, and outbound web traffic that may be encoded, encrypted, or steganographic. Relationship context also links Daserf to BRONZE BUTLER, but local detection should be based on observed behaviors and telemetry, not attribution assumptions.

Likely telemetry

  • Windows endpoint process creation and command-line telemetry
  • Endpoint file creation, modification, and execution metadata
  • Memory access events involving LSASS where available
  • Code-signing and certificate metadata for executed binaries
  • EDR or host telemetry for keylogging, screen capture, and suspicious API use where available

Detection direction

  • Map current detections to the related ATT&CK techniques, especially T1003.001, T1056.001, T1059.003, T1071.001, T1105, T1113, T1132.001, T1560/T1560.001, T1573.001, and T1001.002.
  • Tune detections to correlate multiple weak signals: suspicious Windows command shell use, LSASS access, new archive creation, screen capture/keylogging indicators, and unusual outbound web sessions are more meaningful together than alone.
  • Validate blind spots around encrypted or encoded web traffic, because the related C2 techniques may reduce the value of simple content inspection.
  • Review allowlisting and trust decisions for signed executables; code signing alone should not be treated as proof of legitimacy.
  • Account for false positives from administrative tools, backup/compression utilities, remote support software, and legitimate web applications by baselining expected hosts, users, paths, and destinations.

Mitigation priorities

  • Harden Windows credential exposure first: restrict administrative privileges, monitor and reduce unnecessary LSASS access, and prepare rapid credential reset procedures for suspected compromise.
  • Improve endpoint control quality: application control, least privilege, and scrutiny of unusual signed, packed, or obfuscated executables can reduce reliance on static malware naming.
  • Strengthen egress monitoring and filtering for unusual web-based outbound communications, including destinations, timing, volume, and encoded or encrypted patterns inconsistent with business use.
  • Ensure SOC and IR playbooks cover backdoor behaviors: credential access, collection, archive staging, tool transfer, and C2 containment.
  • Use the Daserf technique relationships as a control-validation checklist for managed detection, incident response exercises, and compliance evidence on sensitive Windows assets.
Analyst notes and limits

The strongest decision value comes from the relationship set: Daserf is modeled as a Windows backdoor with behaviors spanning credential access, collection, execution, defense evasion, and command-and-control. The related group context names BRONZE BUTLER and describes historical targeting, but this take does not infer current targeting or active exploitation.

The official ATT&CK object does not specify Daserf tactics, aliases, labels, or a detection section. External references are limited to the supplied Trend Micro and Secureworks reporting metadata. Environment-specific conclusions require local endpoint, identity, and network evidence.

Official MITRE ATT&CK definition

Daserf

Daserf is a backdoor that has been used to spy on and steal from Japanese, South Korean, Russian, Singaporean, and Chinese victims. Researchers have identified versions written in both Visual C and Delphi. [1] [2]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Techniques used

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

16 rows
Domain ID Name Relationship / procedure
Enterprise T1059.003 Windows Command Shell Sub-technique

Daserf can execute shell commands.CitationTrend Micro Daserf Nov 2017CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1553.002 Code Signing Sub-technique

Some Daserf samples were signed with a stolen digital certificate.CitationSymantec Tick Apr 2016
Enterprise T1105 Ingress Tool Transfer

Daserf can download remote files.CitationTrend Micro Daserf Nov 2017CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1027.002 Software Packing Sub-technique

A version of Daserf uses the MPRESS packer.CitationTrend Micro Daserf Nov 2017
Enterprise T1132.001 Standard Encoding Sub-technique

Daserf uses custom base64 encoding to obfuscate HTTP traffic.CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1560.001 Archive via Utility Sub-technique

Daserf hides collected data in password-protected .rar archives.CitationSymantec Tick Apr 2016
Enterprise T1113 Screen Capture

Daserf can take screenshots.CitationTrend Micro Daserf Nov 2017CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1027 Obfuscated Files or Information

Daserf uses encrypted Windows APIs and also encrypts data using the alternative base64+RC4 or the Caesar cipher.CitationTrend Micro Daserf Nov 2017
Enterprise T1001.002 Steganography Sub-technique

Daserf can use steganography to hide malicious code downloaded to the victim.CitationTrend Micro Daserf Nov 2017
Enterprise T1573.001 Symmetric Cryptography Sub-technique

Daserf uses RC4 encryption to obfuscate HTTP traffic.CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1036.005 Match Legitimate Resource Name or Location Sub-technique

Daserf uses file and folder names related to legitimate programs in order to blend in, such as HP, Intel, Adobe, and perflogs.CitationSymantec Tick Apr 2016
Enterprise T1056.001 Keylogging Sub-technique

Daserf can log keystrokes.CitationTrend Micro Daserf Nov 2017CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1071.001 Web Protocols Sub-technique

Daserf uses HTTP for C2.CitationSecureworks BRONZE BUTLER Oct 2017
Enterprise T1003.001 LSASS Memory Sub-technique

Daserf leverages Mimikatz and Windows Credential Editor to steal credentials.CitationSymantec Tick Apr 2016
Enterprise T1560 Archive Collected Data

Daserf hides collected data in password-protected .rar archives.CitationSymantec Tick Apr 2016
Enterprise T1027.005 Indicator Removal from Tools Sub-technique

Analysis of Daserf has shown that it regularly undergoes technical improvements to evade anti-virus detection.CitationTrend Micro Daserf Nov 2017
Associated objects

Groups, software, and campaigns

Group Enterprise

G0060: BRONZE BUTLER

BRONZE BUTLER is a cyber espionage group with likely Chinese origins that has been active since at least 2008. The group primarily targets Japanese organizations, particularly those in government, biotechnology, electronics manufacturing, and industrial chemistry.[1][2][3]

Relationship explorer

All related ATT&CK context

uses · Technique T1059.003: Windows Command Shell Enterprise uses · Technique T1553.002: Code Signing Enterprise uses · Technique T1105: Ingress Tool Transfer Enterprise uses · Technique T1027.002: Software Packing Enterprise uses · Technique T1132.001: Standard Encoding Enterprise uses · Technique T1560.001: Archive via Utility Enterprise uses · Technique T1113: Screen Capture Enterprise uses · Technique T1027: Obfuscated Files or Information Enterprise uses · Technique T1001.002: Steganography Enterprise uses · Technique T1573.001: Symmetric Cryptography Enterprise uses · Technique T1036.005: Match Legitimate Resource Name or Location Enterprise uses · Technique T1056.001: Keylogging Enterprise uses · Technique T1071.001: Web Protocols Enterprise uses · Technique T1003.001: LSASS Memory Enterprise uses · Technique T1560: Archive Collected Data Enterprise uses · Technique T1027.005: Indicator Removal from Tools Enterprise uses · Group G0060: BRONZE BUTLER Enterprise
Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates .

ATT&CK release
19.1
Object version
1.1
Created
Modified
Raw hash
0298ca1bc71dcd71...
Imported snapshots across ATT&CK releases (1)
Release Bundle imported Object version Modified Status Raw hash
19.1 1.1 Current bundle 0298ca1bc71d…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Open mirrored raw JSON Open MITRE-hosted copy
Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    Trend Micro Daserf Nov 2017

    Chen, J. and Hsieh, M. (2017, November 7). REDBALDKNIGHT/BRONZE BUTLER’s Daserf Backdoor Now Using Steganography. Retrieved December 27, 2017.

    Open source URL
  2. [2]
    Secureworks BRONZE BUTLER Oct 2017

    Counter Threat Unit Research Team. (2017, October 12). BRONZE BUTLER Targets Japanese Enterprises. Retrieved January 4, 2018.

    Open source URL
  3. [3]
    Daserf

    (Citation: Trend Micro Daserf Nov 2017)

  4. [4]
    Muirim

    (Citation: Trend Micro Daserf Nov 2017)

  5. [5]
    Nioupale

    (Citation: Trend Micro Daserf Nov 2017)

  6. [6]
    mitre-attack S0187
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.

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