The Week in Review from Stamus Labs

Welcome to the weekly threat detection update report from Stamus Networks. Each week, you will receive this email with a summary of the updates.

Current Stamus Threat Intelligence (STI) release version: 1525

This week, in addition to daily ruleset and IOC updates, we provided Stamus Security Platform customers with the following improved defense(s):

New threat detection(s) added [1]: 2 (Misconfigured Application, CastleRAT)
Major changes to detections(s) [2]: 144
Updated threat detection(s) [3]: 153

Note: a "method" as referenced below, is a discrete detection vector for a given threat.

New Threat(s) Detected

The following detections were added to your Stamus NDR this past week:

CastleRAT (RAT)

CastleRAT is a RAT found in C and Python variants using a custom binary protocol with RC4 encryption. It queries ip-api[.]com for victim location, supports remote commands, and the C variant has additional features like keylogging.

Splunk | Triage |

Total number of detection methods: 9
Kill chain phase(s): command and control
MITRE ATT&CK: T1041

Major Detection Changes

The following detections were updated this past week with changes to kill chain phase(s) or MITRE ATT&CK tactic(s)/technique(s):

Bitter (APT)

China's APT17 is a threat group targeting U.S. government entities, defense industry, law firms, IT companies, mining companies, and NGOs with network intrusions.

Added kill chain phase(s): command and control
Previously supported kill chain phase(s): command and control, delivery, actions on objectives
MITRE ATT&CK added: T1041
Previously existing MITRE ATT&CK: T1041, T1071
Methods added: 3

CastleLoader (Loader)

CastleLoader is a loader malware that surfaced in early 2025, distributing information stealers and RATs through Cloudflare-themed phishing attacks and fake Github repositories.

Added kill chain phase(s): delivery
Previously supported kill chain phase(s): command and control, actions on objectives, delivery
MITRE ATT&CK added: T1041
Previously existing MITRE ATT&CK: T1071, T1189, T1105, T1041
Methods added: 2

ClickFix (Phishing)

In April 2024, researchers found compromised sites leading to an iframe on pley[.]es showing an error message. The payload domain was taken offline, preventing infection. Later, the iframe was replaced with the ClearFake inject.

Added kill chain phase(s): delivery, command and control
Previously supported kill chain phase(s): exploitation, delivery, command and control
MITRE ATT&CK added: T1189
Previously existing MITRE ATT&CK: T1071, T1027, T1189, T1102, T1036, T1105
Methods added: 8

Doina Loader (Loader)

Loaders are remote access Trojans allowing attackers to control compromised computers. These often lightweight to avoid detection by security technology, some now include advanced features like UI and self-healing capabilities.

Added kill chain phase(s): delivery, actions on objectives, command and control
Previously supported kill chain phase(s): command and control, delivery
MITRE ATT&CK added: T1071
Previously existing MITRE ATT&CK: T1105, T1071
Methods added: 5

Fake Browser (Trojan)

Attackers infect enterprise networks with malware by promoting fake browser updates on hacked websites, leading to the installation of banking trojans and later ransomware encryption on compromised networks.

Added kill chain phase(s): exploitation
Previously supported kill chain phase(s): delivery, exploitation, command and control
MITRE ATT&CK added: T1189
Previously existing MITRE ATT&CK: T1071, T1189
Methods added: 3

LandUpdate808 (Trojan)

Fake update variants like SocGholish, Clear Fake, Smart Ape, and ClickFix are being tracked by a collaboration introducing the LandUpdate808 Fake Update Variant.

Added kill chain phase(s): command and control
Previously supported kill chain phase(s): delivery, command and control, actions on objectives
MITRE ATT&CK added: T1189
Previously existing MITRE ATT&CK: T1189, T1105, T1071
Methods added: 15

Lumma (Data Theft)

Lumma is a C-based information stealer sold on Russian underground forums and Telegram by LummaC since August 2022. It targets cryptocurrency wallets and has file grabber capabilities.

Added kill chain phase(s): command and control, actions on objectives
Previously supported kill chain phase(s): actions on objectives, command and control, installation, delivery
MITRE ATT&CK added: T1071
Previously existing MITRE ATT&CK: T1005, T1071, T1573, T1105
Methods added: 57

NetSupport RAT (RAT)

Remote Access Trojans allow covert surveillance and unauthorized access to victim PCs, collecting keystrokes, passwords, screenshots, and more. They differ from keyloggers by providing remote access capabilities to attackers.

Added kill chain phase(s): command and control
Previously supported kill chain phase(s): actions on objectives, command and control, exploitation, installation
MITRE ATT&CK added: T1105
Previously existing MITRE ATT&CK: T1071, T1105
Methods added: 3

Powershell (Lateral Movement)

Adversaries can abuse PowerShell for execution, discovery, and code running. Examples include Start-Process and Invoke-Command cmdlets, requiring administrator permissions for remote connections.

Added kill chain phase(s): delivery
Previously supported kill chain phase(s): actions on objectives, command and control, delivery, installation
MITRE ATT&CK added: T1105
Previously existing MITRE ATT&CK: T1071, T1027, T1041, T1105
Methods added: 1

Stealc (Data Theft)

Stealc, introduced by actor Plymouth on underground forums, written in C, can steal data from web browsers, crypto wallets, email clients, and messaging apps, built on Vidar, Raccoon, Mars, and RedLine.

Added kill chain phase(s): delivery, command and control
Previously supported kill chain phase(s): command and control, exploitation, delivery
MITRE ATT&CK added: T1105, T1071
Previously existing MITRE ATT&CK: T1071
Methods added: 8

TA456 (APT)

Proofpoint researchers discovered a long-term social engineering and targeted malware campaign by TA456, an Iranian state-aligned threat actor. The attacker used a fake social media persona to send malware to an aerospace defense contractor's employee.

Added kill chain phase(s): command and control
Previously supported kill chain phase(s): delivery, command and control, actions on objectives
MITRE ATT&CK added: T1041
Previously existing MITRE ATT&CK: T1071, T1041, T1102
Methods added: 15

Unknown APT (APT)

Sophisticated adversary with expertise and resources uses multiple attack vectors to establish presence in organizations' IT infrastructure, exfiltrate information, undermine missions, and persistently adapt to defenders.

Added kill chain phase(s): delivery, actions on objectives
Previously supported kill chain phase(s): command and control, delivery, actions on objectives
MITRE ATT&CK added: T1566
Previously existing MITRE ATT&CK: T1041, T1071, T1001, T1566, T1102
Methods added: 8

XWorm (RAT)

Cyble research labs found a malware developer advertising a powerful Windows RAT on the dark web during a threat-hunting exercise.

Added kill chain phase(s): command and control
Previously supported kill chain phase(s): command and control, delivery
MITRE ATT&CK added: T1573
Previously existing MITRE ATT&CK: T1071, T1573
Methods added: 16

Other Threat Detection Update(s)

The following threat detection(s) were improved this past week with new or updated threat methods.

Name of threat	New coverage			Total coverage			Last updated
	New Detection methods	Kill chain phases	Protocols involved	Detection methods	Kill chain phases	Protocols involved
Bitter	3	command and control	dns, tls, http	86	actions on objectives, command and control, delivery	dns, http, tcp, tcp-pkt, tls	2025-12-16
CastleLoader	2	delivery	http	9	actions on objectives, command and control, delivery	http	2025-12-18
CastleRAT	9	command and control	tcp	9	command and control	tcp	2025-12-19
ClickFix	8	delivery, command and control	http, dns, tls	246	command and control, delivery, exploitation	dns, http, tls	2025-12-18
Doina Loader	5	delivery, actions on objectives, command and control	http, dns, tls	18	actions on objectives, command and control, delivery	dns, http, tls	2025-12-19
Fake Browser	3	exploitation	dns, tls, http	1820	command and control, delivery, exploitation	dns, http, tls	2025-12-16
LandUpdate808	15	command and control	dns, tls, http	709	actions on objectives, command and control, delivery	dns, http, tls	2025-12-20
Lumma	57	command and control, actions on objectives	dns, tls, http	7141	actions on objectives, command and control, delivery, installation	dns, http, tls	2025-12-20
NetSupport RAT	3	command and control	http	177	actions on objectives, command and control, exploitation, installation	dns, http, tls	2025-12-20
Powershell	1	delivery	http	67	actions on objectives, command and control, delivery, installation	dns, http, tcp, tcp-pkt, tls	2025-12-19
Stealc	8	delivery, command and control	http	36	command and control, delivery, exploitation	http	2025-12-18
TA456	15	command and control	dns, tls, http	146	actions on objectives, command and control, delivery	dns, http, tls	2025-12-17
Unknown APT	8	delivery, actions on objectives	dns, tls, http	1838	actions on objectives, command and control, delivery	dns, http, tcp, tls	2025-12-20
XWorm	16	command and control	tcp-pkt	4275	command and control, delivery	dns, http, tcp, tcp-pkt, tls	2025-12-16

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