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MalwareRansomwareUsed by 1 actor

YouieLoader

YouieLoader is malware associated with the North Korean threat actor Moonstone Sleet. Based on the provided content, it functions as an intermediate loader used alongside SplitLoader and is capable of capturing victim system browser information. The content also attributes system owner/user discovery functionality to YouieLoader and states that Moonstone Sleet used loader malware such as YouieLoader to create malicious Windows services for execution. In the broader intrusion context described, Moonstone Sleet delivered malware through phishing and trojanized software, staged payloads on adversary-controlled VPS infrastructure, retrieved additional payloads over web protocols, and used persistence and execution mechanisms including Registry Run keys, scheduled tasks, and service creation. High-confidence details specific to YouieLoader from the content are that it is a Moonstone Sleet-deployed loader malware family that captures browser information from victim systems, performs user/system owner discovery, and is used in service-based execution chains.

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THREAT ACTORS

Groups observed using it

1 distinct threat actor attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.

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Moonstone Sleet

Moonstone Sleet deployed malware such as YouieLoader capable of capturing victim system browser information.

via mitre attack websiteattack.mitre.org
MITRE ATT&CK

Techniques & procedures

3 distinct techniques documented for this family, organized by ATT&CK tactic.

Execution

1 technique
T1569.002Service ExecutionEvidence1
TacticExecution

Moonstone Sleet used intermediate loader malware such as YouieLoader and SplitLoader that create malicious services.

Discovery

2 techniques
T1033System Owner/User DiscoveryEvidence2
TacticDiscovery

The content repeatedly describes malware and threat actors collecting usernames, identifying logged-in users, running whoami/query user/quser, checking admin status, and enumerating user sessions.

T1217Browser Information DiscoveryEvidence3
TacticDiscovery

APT38 has collected browser bookmark information to learn more about compromised hosts, obtain personal information about users, and acquire details about internal network resources.

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Threat actor attribution1

Named campaigns wielding this family, with evidence pinned to each claim.

Exploited vulnerabilities

CVEs this family uses for access and lateral movement.

Detection signatures

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MITRE ATT&CK mapping3

Every documented technique, ranked by evidence weight.

Researcher chatter

Reddit, Mastodon, and CTI community discussion around this family.