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FrostyNeighbor

actor · actor:frostyneighbor single-source-national-cert

Long-running cyberespionage group that ESET assesses as apparently aligned with Belarus, active since at least 2016 per Mandiant, using PicassoLoader downloaders to deliver Cobalt Strike against targets in Ukraine, Poland and Lithuania (ESET; Mandiant).

Aliases: Ghostwriter, UNC1151, UAC-0057, TA445, PUSHCHA, Storm-0257

Coverage
4
1 about it · 3 mentions · first 2026-05-08 → last 2026-10-21
Latest activity
2026-05-15
Belarus-aligned FrostyNeighbor hits Ukrainian government bodies with geofenced PDF lures and Cobalt Strike
Peak priority
notable
1 notable
Targets
public-sector
sectors: public-sector · regions: europe
Sources cited
8
6 hosts
2026-05-084 appearances2026-07-09

Defender insights

What each entry about FrostyNeighbor tells a defender to do, newest first.

2026-05-15NOTABLEBelarus-aligned FrostyNeighbor hits Ukrainian government bodies with geofenced PDF lures and Cobalt Strike

Exposure · triage · detection

Relationships explore in graph

Typed, source-stated connections from the entity registry; each edge cites the entry whose reporting establishes it.

attributed activity

Story timeline

Every entry that names FrostyNeighbor, newest first. Rows tagged mention only name it in passing: they are listed for completeness and add nothing to the action items, pivots or ATT&CK profile on this page.

  1. 2026-07-09CERT Polska: UNC1151/Ghostwriter shifts to Gmail with real-time 2FA-relay phishing against officials and public administration
    mentionactive-threatsCERT-PL: Ghostwriter/UNC1151 now phishes Gmail with a live 2FA-relay panel that defeats TOTP and SMS
  2. 2026-05-23Ghostwriter / UAC-0057 / FrostyNeighbor, CERT-UA documents new OYSTERFRESH → OYSTERBLUES → OYSTERSHUCK implant chain via Prometheus learning-platform lures
    mentionactive-threats
  3. 2026-05-15FrostyNeighbor (Ghostwriter, UNC1151): since March 2026, geofenced PDF lures deliver a JavaScript PicassoLoader and Cobalt Strike to Ukrainian government organisations
    active-threatsBelarus-aligned FrostyNeighbor hits Ukrainian government bodies with geofenced PDF lures and Cobalt Strike
  4. 2026-05-08Poland's ABW: attackers breached five municipal water treatment plants in 2025 and in some cases altered equipment parameters, and hacktivists exploited weak passwords on exposed management panels at municipal sites
    mentionactive-threatsABW reports breaches at five Polish water plants in 2025, with equipment settings altered in some cases, naming no actor or access route
ATT&CK techniques (13 across 7 tactics)

13 techniques observed across 1 entry about this entity, derived from entry metadata and body evidence, never asserted without a published entry behind it · pinned to MITRE ATT&CK v20.0 · compare on the matrix · Navigator layer (JSON)

  • Initial AccessPhishing: Spearphishing Attachment
  • ExecutionScheduled Task/Job: Scheduled Task · Command and Scripting Interpreter: JavaScript · User Execution: Malicious File
  • PersistenceScheduled Task/Job: Scheduled Task · Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder
  • Privilege EscalationScheduled Task/Job: Scheduled Task · Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder
  • StealthObfuscated Files or Information · Masquerading: Rename Legitimate Utilities · Deobfuscate/Decode Files or Information · System Binary Proxy Execution: Rundll32
  • DiscoveryProcess Discovery · System Information Discovery
  • Command and ControlApplication Layer Protocol: Web Protocols · Ingress Tool Transfer

Initial Access TA0001

T1566.001Phishing: Spearphishing Attachment×1

Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Execution TA0002

T1053.005Scheduled Task/Job: Scheduled Task×1

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1059.007Command and Scripting Interpreter: JavaScript×1

Adversaries may abuse various implementations of JavaScript for execution. JavaScript (JS) is a platform-independent scripting language (compiled just-in-time at runtime) commonly associated with scripts in webpages, though JS can be executed in runtime environments outside the browser.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1204.002User Execution: Malicious File×1

An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, .cpl, .reg, and .iso.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Persistence TA0003

T1053.005Scheduled Task/Job: Scheduled Task×1

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1547.001Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder×1

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Privilege Escalation TA0004

T1053.005Scheduled Task/Job: Scheduled Task×1

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1547.001Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder×1

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Stealth TA0005

T1027Obfuscated Files or Information×1

Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1036.003Masquerading: Rename Legitimate Utilities×1

Adversaries may rename legitimate / system utilities to try to evade security mechanisms concerning the usage of those utilities. Security monitoring and control mechanisms may be in place for legitimate utilities adversaries are capable of abusing, including both built-in binaries and tools such as PSExec, AutoHotKey, and IronPython. It may be possible to bypass those security mechanisms by renaming the utility prior to utilization (ex: rename <code>rundll32.exe</code>). An alternative case occurs when a legitimate utility is copied or moved to a different directory and renamed to avoid detections based on these utilities executing from non-standard paths.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1140Deobfuscate/Decode Files or Information×1

Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1218.011System Binary Proxy Execution: Rundll32×1

Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, vice executing directly (i.e. Shared Modules), may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads (ex: <code>rundll32.exe {DLLname, DLLfunction}</code>).

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Discovery TA0007

T1057Process Discovery×1

Adversaries may attempt to get information about running processes on a system. Information obtained could be used to gain an understanding of common software/applications running on systems within the network. Administrator or otherwise elevated access may provide better process details. Adversaries may use the information from Process Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1082System Information Discovery×1

An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Adversaries may use this information to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. This behavior is distinct from Local Storage Discovery which is an adversary's discovery of local drive, disks and/or volumes.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Command and Control TA0011

T1071.001Application Layer Protocol: Web Protocols×1

Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

T1105Ingress Tool Transfer×1

Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer).

Evidence: 2026-05-15/frostyneighbor-ghostwriter-unc1151-belarus-state-aligned-ese · ATT&CK page ↗

Entries about FrostyNeighbor (1)

2026-05-15 · view entry permalink →

NOTABLEupdatedNATOB2

FrostyNeighbor (Ghostwriter, UNC1151): since March 2026, geofenced PDF lures deliver a JavaScript PicassoLoader and Cobalt Strike to Ukrainian government organisations

ESET attributes new activity since March 2026 to FrostyNeighbor, also known as Ghostwriter, UNC1151, UAC-0057, TA445, PUSHCHA or Storm-0257, a long-running cyberespionage group apparently aligned with the interests of Belarus, using links in spearphishing PDFs to target governmental organisations in Ukraine (ESET, 2026-05-14). In ESET's telemetry the group's Ukrainian targeting focuses on military, defence and government, while its victimology in Poland and Lithuania is broader, spanning industry and manufacturing, healthcare and pharmaceuticals, logistics and many governmental organisations (ESET, 2026-05-14).

The lure is a blurred PDF impersonating Ukrtelecom whose download button leads to the group's delivery server; visitors outside Ukraine receive a benign PDF of the same name, while Ukrainian IP addresses receive a RAR archive holding a JavaScript first stage that shows a decoy, re-runs itself, drops a base64-embedded JavaScript PicassoLoader and builds a scheduled task from an XML template the C2 serves as a fake JPG (ESET, 2026-05-14). PicassoLoader collects the username, computer name, OS version, boot time, current time and running processes, posts them over HTTPS every 10 minutes and evaluates any response longer than 100 bytes (ESET, 2026-05-14). Operators very likely decide by hand whether the victim is of interest; if so, the C2 returns a third-stage dropper that copies rundll32.exe into %ProgramData% under another name, writes the base64-decoded Cobalt Strike beacon DLL beside it, and registers in the HKCU Run key a LNK that starts the copied rundll32 with the DLL's export (ESET, 2026-05-14).

Triage: rundll32.exe is a normal Windows binary when it runs from the system directory; a copy of it under a different name in %ProgramData%, which ESET says is very likely meant to bypass detection rules, is the signal (ESET, 2026-05-14).

Since March 2026, we have detected new activities that we attributed to FrostyNeighbor, using links in malicious PDFs sent via spearphishing attachments to target governmental organizations in Ukraine.

The decision whether or not to deliver a payload is very likely manually performed by the operators, based on the collected information to decide if the victim is of interest.

The payload is only delivered after server-side victim validation, combining automated checks of the requesting user agent and IP address with the manual validation by the operators.

ESET 2026-05-14
Correctionrun 2026-10-21T1148Z-auditaffected_productsbodyclassificationevidenceheadlinesectorssourcessourcing_notesummarytagstechniquestitleentities

The activity ESET documents since March 2026 targets governmental organisations in Ukraine (ESET, 2026-05-14); the industrial, healthcare and pharmaceutical, logistics and governmental victims in Poland and Lithuania come from ESET's introduction to the group's broader victimology, not from this campaign wave. The chain also persists: the first stage builds a scheduled task from a downloaded XML template to run PicassoLoader, and the Cobalt Strike stage copies rundll32.exe into %ProgramData% under another name and starts it from a LNK registered in the HKCU Run key (ESET, 2026-05-14), which gives defenders host artefacts to hunt where geofencing hides the network side.

threat15 May 05:00Zmulti-sourceOpen finding →
Sources: ESET · The Hacker News

Co-occurring entities

Derived: referenced by the same focused operational entries (weekly summaries and report roundups don't count); ×N counts the shared entries.

Where this entity is cited

  • Threats4

Source distribution

  • abw.gov.pl2 (25%)
  • thehackernews.com2 (25%)
  • cert.pl1 (12%)
  • cyberdefence24.pl1 (12%)
  • scworld.com1 (12%)
  • welivesecurity.com1 (12%)