S9013: DRYHOOK

DRYHOOK matters because ATT&CK describes it as a Python credential-stealing script on Linux and network-device platforms. For leaders, the practical risk is not just malware execution; it is the possibility that credentials, authentication paths, and security visibility on infrastructure devices could be weakened before defenders have complete endpoint-style telemetry.

Executive priority

Treat this as a control-validation prompt for internet-facing Linux and network-device environments, especially VPN or appliance workflows referenced by the supplied sources. Executives should ask whether security teams can prove they collect administrative CLI activity, authentication changes, service/tool tampering, local staging evidence, and image/configuration integrity signals from network devices—not only from traditional endpoints.

Technical view

ATT&CK provides no official detection text for DRYHOOK, so SOC and IR teams should validate coverage through the related behaviors: Python execution, network-device CLI execution, keylogging-oriented credential collection, local data staging, Linux permission changes, authentication-process modification, network-device authentication changes, system-image modification, service stopping, security-tool tampering, and encoded/encrypted file artifacts. The highest-value validation is whether Linux and network-device logs can show suspicious interpreter use, unexpected administrative commands, authentication component changes, and loss or degradation of monitoring services.

Likely telemetry

Linux process execution and command-line telemetry for Python scripts
Network device administrative CLI logs and command history where available
Authentication logs for Linux systems, identity-facing appliances, and network devices
File integrity or configuration monitoring for authentication components, permissions, and sensitive directories
Network device firmware, system image, and configuration integrity evidence

Detection direction

Do not rely on a DRYHOOK-specific signature; ATT&CK does not provide detection guidance for this object.
Baseline legitimate Python usage on Linux systems and investigate Python execution in unusual paths, by unexpected users, or near authentication data handling.
Correlate network-device CLI activity with admin identity, change windows, and configuration/image changes; many organizations lack durable appliance command telemetry.
Tune for combinations of behaviors: credential-access indicators plus local staging, permission changes, authentication-process modification, or service/security-tool disruption.
Treat service stops and monitoring-agent failures as investigation pivots, not standalone proof of DRYHOOK, because administrative maintenance can create false positives.

Mitigation priorities

Prioritize hardening and timely remediation for externally exposed Linux and network-device appliances covered by vulnerability-management programs.
Restrict and monitor administrative access to network devices and Linux hosts, including strong authentication, least privilege, and change-control evidence.
Reduce unnecessary Python/script execution paths on sensitive systems and monitor approved interpreter use.
Maintain integrity baselines and recoverable known-good images/configurations for network devices and authentication components.
Protect logging and security tooling from tampering; alert on service stoppage, agent degradation, or configuration changes that reduce visibility.

Additional notes and limits

The supplied ATT&CK relationships make DRYHOOK more material than a generic script because they connect credential theft with execution, staging, defense impairment, authentication modification, and network-device system-image risk. The official description also states prior use by PRC state-affiliated actors identified as UNC5221 and SYLVANITE, but this take does not infer current activity or customer exposure.

ATT&CK provides no official detection text, no aliases, and no malware-specific tactics for this object. Coverage decisions require local evidence about Linux logging depth, network-device telemetry, appliance exposure, administrative workflows, and whether configuration/image integrity is monitored.

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

Official MITRE ATT&CK definition

DRYHOOK

DRYHOOK is Python script used to steal credentials. DRYHOOK was first reported in January 2025, and has previously been leveraged by People's Republic of China (PRC) state-affiliated threat actors identified as UNC5221 and SYLVANITE.[1][2][3]

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 techniques11 rows

Domain	ID	Name	Relationship / procedure
Enterprise	T1222.002	Linux and Mac PermissionsSub-technique	DRYHOOK has the ability to remount the filesystem as “read-write” to make changes and then restores it to “read-only” prior to killing processes to apply the modifications.[2][3]
Enterprise	T1056.001	KeyloggingSub-technique	DRYHOOK has captured user credentials and passwords in plaintext and has encrypted them in a stored file on the network device.[2][3]
Enterprise	T1074.001	Local Data StagingSub-technique	DRYHOOK has stored stolen credentials for future use in the temp folder of a victimized Ivanti Connect Secure VPN device, specifically in the file location `/tmp/cmmmap.kumMW`.[2][3]
Enterprise	T1059.008	Network Device CLISub-technique	DRYHOOK has the ability to interact with Ivanti Connect Secure environments and to modify system components.[2][3]
Enterprise	T1601	Modify System Image	DRYHOOK has modified the Ivanti Connect Secure VPN authentication Perl module `DSAuth.pm` by reading its contents in the buffer, then finding and replacing select lines of code.[2][3]
Enterprise	T1685	Disable or Modify Tools	DRYHOOK has killed all instances of the `cgi-server` process in order for the modified Perl module to be activated.[2]
Enterprise	T1027.013	Encrypted/Encoded FileSub-technique	DRYHOOK has encrypted stolen credentials strings within a file using both Base64 and RC4 with a hard-coded key.[2][3]
Enterprise	T1556	Modify Authentication Process	DRYHOOK has intercepted and logged user credentials by modifying the Perl module in Ivanti Connect Secure VPN edge-devices located within `/home/perl/DSAuth.pm`.[2][3]
Enterprise	T1059.006	PythonSub-technique	DRYHOOK is a Python-based script that executes within the victim environment.[2][3]
Enterprise	T1489	Service Stop	DRYHOOK has terminated all instances of the `cgi-server` process before activating the modified DSAuth.pm file.[2]
Enterprise	T1556.004	Network Device AuthenticationSub-technique	DRYHOOK has patched victim appliances authentication routines to capture credentials in plaintext as users log in.[2]

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: 19.1
Object version: 1.0
Created: Apr 14, 2026, 13:25 UTC (UTC+00:00)
Modified: Apr 23, 2026, 03:09 UTC (UTC+00:00)
Raw hash: 9d167e8a352c51af...

Imported snapshots across ATT&CK releases(1)

Release	Bundle imported	Object version	Modified	Status	Raw hash
19.1	Jul 14, 2026, 09:14 UTC (UTC+00:00)	1.0	Apr 23, 2026, 03:09 UTC (UTC+00:00)	Current bundle	`9d167e8a352c…`

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]
Dragos SYLVANITE MuddyWater Electrum March 2026
Dragos. (2026, March 24). Dragos 2026 OT Cybersecurity Report: Year in Review, O&G and Petrochemicals Focus. Retrieved April 17, 2026.
Open source URL
[2]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[3]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[4]
Dragos SYLVANITE MuddyWater Electrum March 2026
Dragos. (2026, March 24). Dragos 2026 OT Cybersecurity Report: Year in Review, O&G and Petrochemicals Focus. Retrieved April 17, 2026.
Open source URL
[5]
Dragos SYLVANITE MuddyWater Electrum March 2026
Dragos. (2026, March 24). Dragos 2026 OT Cybersecurity Report: Year in Review, O&G and Petrochemicals Focus. Retrieved April 17, 2026.
Open source URL
[6]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[7]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[8]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[9]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[10]
mitre-attackS9013
Open source URL
[11]
mitre-attackS9013
Open source URL
[12]
mitre-attackS9013
Open source URL
[13]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[14]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[15]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[16]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[17]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[18]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[19]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[20]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[21]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[22]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[23]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[24]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[25]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[26]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[27]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[28]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[29]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[30]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[31]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[32]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[33]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[34]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[35]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[36]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[37]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[38]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[39]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[40]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[41]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[42]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[43]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[44]
Picus Security UNC5221 Ivanti May 2025
Sila Ozeren Hacioglu. (2025, May 5). UNC5221’s Latest Exploit: Weaponizing CVE-2025-22457 in Ivanti Connect Secure. Retrieved April 13, 2026.
Open source URL
[45]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
Open source URL
[46]
Google UNC5221 Ivanti January 2025
John Wolfram, Josh Murchie, Matt Lin, Daniel Ainsworth, Robert Wallace, Dimiter Andonov, Dhanesh Kizhakkinan, Jacob Thompson. (2025, January 8). Ivanti Connect Secure VPN Targeted in New Zero-Day Exploitation. Retrieved April 14, 2026.
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.

Official MITRE ATT&CK site Official STIX data repository MITRE ATT&CK terms of use