S1226: BOOKWORM

BOOKWORM is a modular trojan known to be leveraged by Mustang Panda and was first observed utilized in 2015. BOOKWORM was later updated in late 2021 and the fall of 2022 to launch shellcode represented as UUID parameters. [1][2][3]

EnterpriseS1226MalwareObject v1.0ModifiedOct 21, 2025, 16:51 UTC (UTC+00:00)

S1226: BOOKWORM describes [BOOKWORM](https://attack.mitre.org/software/S1226) is a modular trojan known to be leveraged by [Mustang Panda](https://attack.mitre.org/groups/G0129) and was first observed utilized in 2015. [BOOKWORM](https://attack.mitre.org/software/S1226) was later updated in late 2021 and the fall of 2022 to launch shellcode represented as UUID parameters. (Citation: Broadcom)(Citation: Unit42 Bookworm Nov2015)(Citation: Palo Alto Networks, Unit 42)

Executive priority

S1226: BOOKWORM is an official MITRE ATT&CK software. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.

Technical view

Security teams should validate S1226: BOOKWORM by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Windows), and available local telemetry before making detection or mitigation decisions.

Likely telemetry

Official ATT&CK relationships and object metadata
Network, endpoint, and security-tool telemetry

Detection direction

Validate whether S1226: BOOKWORM appears in your detection coverage and tabletop scenarios.
Use the object to align executive risk language with SOC, incident response, and detection engineering work.
Do not treat ATT&CK relationship context as attribution without corroborating evidence.

Mitigation priorities

Map the object to existing controls and identify missing telemetry or response ownership.
Prioritize mitigations that reduce exposure on the listed platforms and tactics.
Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.

Additional notes and limits

Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.

This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

BOOKWORM

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.

Filter related techniques17 rows

Domain	ID	Name	Relationship / procedure
Enterprise	T1033	System Owner/User Discovery	BOOKWORM has obtained the username from an infected host. [2]
Enterprise	T1553.002	Code SigningSub-technique	BOOKWORM has used valid legitimate digital signatures and certificates to evade detection. [2]
Enterprise	T1071.001	Web ProtocolsSub-technique	BOOKWORM has communicated with its C2 via HTTP POST requests. [2][3]
Enterprise	T1112	Modify Registry	BOOKWORM has modified Registry key values as part of its created service `DeviceSync`. [2]
Enterprise	T1543.003	Windows ServiceSub-technique	BOOKWORM has created a service named `Microsoft Windows DeviceSync Service` at `HKLM\SYSTEM\CurrentControlSet\Services\DeviceSync\` to trigger execution when the system starts and to maintain persistence. [2]
Enterprise	T1564.003	Hidden WindowSub-technique	BOOKWORM has created a hidden window when conducting key logging and clipboard theft through its KBLogger.dll module.[2]
Enterprise	T1140	Deobfuscate/Decode Files or Information	BOOKWORM has decoded its Base64 encoded payload prior to execution.[3] BOOKWORM has also encrypted files with RC4 and has decrypted its payload prior to execution.[2]
Enterprise	T1574.001	DLLSub-technique	BOOKWORM has used DLL side-loading to execute the malicious payload. [1][3] BOOKWORM has also side-loaded DLL components into a legitimate process, including Microsoft Malware Protection `MsMpEng.exe` and Kaspersky Anti-Virus `ushata.exe`.[2]
Enterprise	T1036.004	Masquerade Task or ServiceSub-technique	BOOKWORM has created services that attempt to resemble legitimate services to include a service named `Microsoft Windows DeviceSync Service`.[2]
Enterprise	T1056.001	KeyloggingSub-technique	BOOKWORM has used its KBLogger.dll module to capture keystrokes and stored them in a folder. [2]
Enterprise	T1106	Native API	BOOKWORM has used various Windows API calls during execution and defense evasion.[1] [3] BOOKWORM has created a buffer on the heap using `HeapCreate` and `HeapAlloc` which allows for copying of shell code and then execution on the heap is initiated through callback function of legitimate API functions such as `EnumChildWindows` or `EnumSystemLanguageGroupsA`. [3]
Enterprise	T1573.001	Symmetric CryptographySub-technique	BOOKWORM has used encryption and compression algorithms to obfuscate the traffic between the system and C2 server, methods observed included RC4, AES, XOR with 0x5a, and LZO. [2]
Enterprise	T1027.013	Encrypted/Encoded FileSub-technique	BOOKWORM has utilized Base64 encoding to obfuscate its payload.[3]
Enterprise	T1027	Obfuscated Files or Information	BOOKWORM has been delivered using self-extracting RAR archives.[2]
Enterprise	T1070.006	TimestompSub-technique	BOOKWORM has modified file timestamps from the export address table (EAT) to make it difficult to discern when the module was created. [3]
Enterprise	T1001.003	Protocol or Service ImpersonationSub-technique	BOOKWORM has modified HTTP POST requests to resemble legitimate communications.[3]
Enterprise	T1115	Clipboard Data	BOOKWORM has used its KBLogger.dll module to steal data saved to the clipboard. [2]

Associated objects

Groups, software, and campaigns

G0129: Mustang Panda

Mustang Panda is a China-based cyber espionage threat actor that has been conducting operations since at least 2012. Mustang Panda has been known to use tailored phishing lures and decoy documents to deliver malicious payloads. Mustang Panda has targeted government, diplomatic, and non-governmental organizations, including think tanks, religious institutions, and research entities, across the United States, Europe, and Asia, with notable activity in Russia, Mongolia, Myanmar, Pakistan, and Vietnam. [1][2][3][4][5][6][7][8][9][10][11][12][13]

Relationship explorer

All related ATT&CK context

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: 19.2
Object version: 1.0
Created: Jul 21, 2025, 19:02 UTC (UTC+00:00)
Modified: Oct 21, 2025, 16:51 UTC (UTC+00:00)
Raw hash: cff78ce71b4b7151...

Imported snapshots across ATT&CK releases(2)

Release	Bundle imported	Object version	Modified	Status	Raw hash
19.2	Aug 6, 2026, 02:58 UTC (UTC+00:00)	1.0	Oct 21, 2025, 16:51 UTC (UTC+00:00)	Current bundle	`cff78ce71b4b…`
19.1	Jul 14, 2026, 09:14 UTC (UTC+00:00)	1.0	Oct 21, 2025, 16:51 UTC (UTC+00:00)	Older bundle	`cff78ce71b4b…`

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]
Broadcom
Broadcom Protection Bulletins. (2025, February 20). Bookworm malware linked to Fireant (aka Stately Tarurus) activity observed in Southeast Asia. Retrieved July 21, 2025.
Open source URL
[2]
Unit42 Bookworm Nov2015
Robert Falcone, Mike Scott, Juan Cortes. (2015, November 10). Bookworm Trojan: A Model of Modular Architecture. Retrieved July 21, 2025.
Open source URL
[3]
Palo Alto Networks, Unit 42
Robert Falcone. (2025, February 20). Stately Taurus Activity in Southeast Asia Links to Bookworm Malware. Retrieved July 21, 2025.
Open source URL
[4]
mitre-attackS1226
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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