Summary The Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) are releasing this joint advisory to disseminate known tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) associated with threat actors deploying the LummaC2 information stealer (infostealer) malware. LummaC2 malware is able to infiltrate victim computer networks and exfiltrate sensitive information, threatening vulnerable individuals’ and organizations’ computer networks across multiple U.S. critical infrastructure sectors. According to FBI information and trusted third-party reporting, this activity has been observed as recently as May 2025. The IOCs included in this advisory were associated with LummaC2 malware infections from November 2023 through May 2025. The FBI and CISA encourage organizations to implement the recommendations in the Mitigations section of this advisory to reduce the likelihood and impact of LummaC2 malware. Download the PDF version of this report: AA25-141B Threat Actors Deploy LummaC2 Malware to Exfiltrate Sensitive Data from Organizations (PDF, 1.28 MB ) For a downloadable copy of IOCs, see: AA25-141B STIX XML (XML, 146.54 KB ) AA25-141B STIX JSON (JSON, 300.90 KB ) Technical Details Note: This advisory uses the MITRE ATT&CK ® Matrix for Enterprise framework, version 17. See the MITRE ATT&CK Tactics and Techniques section of this advisory for threat actor activity mapped to MITRE ATT&CK tactics and techniques. Overview LummaC2 malware first appeared for sale on multiple Russian-language speaking cybercriminal forums in 2022. Threat actors frequently use spearphishing hyperlinks and attachments to deploy LummaC2 malware payloads [ T1566.001 , T1566.002 ]. Additionally, threat actors rely on unsuspecting users to execute the payload by clicking a fake Completely Automated Public Turing Test to tell Computers and Humans Apart (CAPTCHA). The CAPTCHA contains instructions for users to then open the Windows Run window (Windows Button + R) and paste clipboard contents (“CTRL + V”). After users press “enter” a subsequent Base64-encoded PowerShell process is executed. To obfuscate their operations, threat actors have embedded and distributed LummaC2 malware within spoofed or fake popular software (i.e., multimedia player or utility software) [ T1036 ]. The malware’s obfuscation methods allow LummaC2 actors to bypass standard cybersecurity measures, such as Endpoint Detection and Response (EDR) solutions or antivirus programs, designed to flag common phishing attempts or drive-by downloads [ T1027 ]. Once a victim’s computer system is infected, the malware can exfiltrate sensitive user information, including personally identifiable information, financial credentials, cryptocurrency wallets, browser extensions, and multifactor authentication (MFA) details without immediate detection [ TA0010 , T1119 ]. Private sector statistics indicate there were more than 21,000 market listings selling LummaC2 logs on multiple cybercriminal forums from April through June of 2024, a 71.7 percent increase from April through June of 2023. File Execution Upon execution, the LummaC2.exe file will enter its main routine, which includes four sub-routines (see Figure 1 ). Figure 1. LummaC2 Main Routine The first routine decrypts strings for a message box that is displayed to the user (see Figure 2 ). Figure 2. Message Box If the user selects No , the malware will exit. If the user selects Yes , the malware will move on to its next routine, which decrypts its callback Command and Control (C2) domains [ T1140 ]. A list of observed domains is included in the Indicators of Compromise section. After each domain is decoded, the implant will attempt a POST request [ T1071.001 ] (see Figure 3 ). Figure 3. Post Request If the POST request is successful, a pointer to the decoded domain string is saved in a global variable for later use in the main C2 routine used to retrieve JSON formatted commands (see Figure 4 ). Figure 4. Code Saving Successful Callback Request Once a valid C2 domain is contacted and saved, the malware moves on to the next routine, which queries the user’s name and computer name utilizing the Application Programming Interfaces (APIs) GetUserNameW and GetComputerNameW respectively [ T1012 ]. The returned data is then hashed and compared against a hard-coded hash value (see Figure 5 ). Figure 5. User and Computer Name Check The hashing routine was not identified as a standard algorithm; however, it is a simple routine that converts a Unicode string to a 32-bit hexadecimal value. If the username hash is equal to the value 0x56CF7626 , then the computer name is queried. If the computer name queried is seven characters long, then the name is hashed and checked against the hard-coded value of 0xB09406C7 . If both values match, a final subroutine will be called with a static value of the computer name hash as an argument. If this routine is reached, the process will terminate. This is most likely a failsafe to prevent the malware from running on the attacker’s system, as its algorithms are one-way only and will not reveal information on the details of the attacker’s own hostname and username. If the username and hostname check function returns zero (does not match the hard-coded values), the malware will enter its main callback routine. The LummaC2 malware will contact the saved hostname from the previous check and send the following POST request (see Figure 6 ). Figure 6. Second POST Request The data returned from the C2 server is encrypted. Once decoded, the C2 data is in a JSON format and is parsed by the LummaC2 malware. The C2 uses the JSON configuration to parse its browser extensions and target lists using the ex key, which contains an array of objects (see Figure 7 ). Figure 7. Parsing of ex JSON Value Parsing the c key contains an array of objects, which will give the implant its C2 (see Figure 8 ). Figure 8. Parsing of c JSON Value C2 Instructions Each array object that contains the JSON key value of t will be evaluated as a command opcode, resulting in the C2 instructions in the subsections below. 1. Opcode 0 – Steal Data Generic This command allows five fields to be defined when stealing data, offering the most flexibility. The Opcode O command option allows LummaC2 affiliates to add their custom information gathering details (see Table 1 ). Table 2. Opcode 1 Options Key Value p Path to steal from m File extensions to read z Output directory to store stolen data d Depth of recursiveness fs Maximum file size 2. Opcode 1 – Steal Browser Data This command only allows for two options: a path and the name of the output directory. This command, based on sample configuration downloads, is used for browser data theft for everything except Mozilla [ T1217 ] (see Table 2 ). Table 2. Opcode 1 Options Key Value p Path to steal from z Name of Browser – Output 3. Opcode 2 – Steal Browser Data (Mozilla) This command is identical to Opcode 1 ; however, this option seems to be utilized solely for Mozilla browser data (see Table 3 ). Table 3. Opcode 2 Options Key Value p Path to steal from z Name of Browser – Output 4. Opcode 3 – Download a File This command contains three options: a URL, file extension, and execution type. The configuration can specify a remote file with u to download and create the extension specified in the ft key [ T1105 ] (see Table 4 ). Table 4. Opcode 3 Options Key Value u URL for Download ft File Extension e  Execution Type The e value can take two values: 0 or 1 . This specifies how to execute the downloaded file either with the LoadLibrary API or via the command line with rundll32.exe [ T1106 ] (see Table 5 ). Table 5. Execution Types Key Value e=0 Execute with LoadLibraryW() e=1 Executive with rund1132.exe 5. Take Screenshot If the configuration JSON file has a key of “ se ” and its value is “ true ,” the malware will take a screenshot in BMP format and upload it to the C2 server. 6. Delete Self If the configuration JSON file has a key of “ ad ” and its value is “ true ,” the malware will enter a routine to delete itself. The command shown in Figure 9 will be decoded and executed for self-deletion. Figure 9. Self-Deletion Command Line Figure 10 depicts the above command line during execution. Figure 10. Decoded Command Line in Memory Host Modifications Without any C2 interactions, the LummaC2 malware does not create any files on the infected drive. It simply runs in memory, gathers system information, and exfiltrates it to the C2 server [ T1082 ]. The commands returned from the C2 server could indicate that it drops additional files and/or saves data to files on the local hard drive. This is variable, as these commands come from the C2 server and are mutable. Decrypted Strings Below is a list of hard-coded decrypted strings located in the binary (see Figure 11 ). Figure 11. Decoded Strings Indicators of Compromise See Table 6 and Table 7 for LummaC2 IOCs obtained by the FBI and trusted third parties. Disclaimer: The authoring agencies recommend organizations investigate and vet these indicators of compromise prior to taking action, such as blocking. Table 6. LummaC2 Executable Hashes Executables Type 4AFDC05708B8B39C82E60ABE3ACE55DB ( LummaC2.exe from November 2023) MD5 E05DF8EE759E2C955ACC8D8A47A08F42 ( LummaC2.exe from November 2023) MD5 C7610AE28655D6C1BCE88B5D09624FEF MD5 1239288A5876C09D9F0A67BCFD645735168A7C80 ( LummaC2.exe from November 2023) SHA1 B66DA4280C6D72ADCC68330F6BD793DF56A853CB ( LummaC2.exe from November 2023) SHA1 3B267FA5E1D1B18411C22E97B367258986E871E5 TLSH 19CC41A0A056E503CC2137E19E952814FBDF14F8D83F799AEA9B96ABFF11EFBB (November 2023) SHA256 2F31D00FEEFE181F2D8B69033B382462FF19C35367753E6906ED80F815A7924F ( LummaC2.exe from November 2023) SHA256 4D74F8E12FF69318BE5EB383B4E56178817E84E83D3607213160276A7328AB5D SHA256 325daeb781f3416a383343820064c8e98f2e31753cd71d76a886fe0dbb4fe59a SHA256 76e4962b8ccd2e6fd6972d9c3264ccb6738ddb16066588dfcb223222aaa88f3c SHA256 7a35008a1a1ae3d093703c3a34a21993409af42eb61161aad1b6ae4afa8bbb70 SHA256 a9e9d7770ff948bb65c0db24431f75dd934a803181afa22b6b014fac9a162dab SHA256 b287c0bc239b434b90eef01bcbd00ff48192b7cbeb540e568b8cdcdc26f90959 SHA256 ca47c8710c4ffb4908a42bd986b14cddcca39e30bb0b11ed5ca16fe8922a468b SHA256 Table 7. LummaC2 DLL Binaries DLL Binaries Type iphlpapi.dll IP Helper API winhttp.dll Windows HTTP Services The following are domains observed deploying LummaC2 malware. Disclaimer: The domains below are historical in nature and may not currently be malicious. Pinkipinevazzey[.]pw Fragnantbui[.]shop Medicinebuckerrysa[.]pw Musicallyageop[.]pw stogeneratmns[.]shop wallkedsleeoi[.]shop Tirechinecarpet[.]pw reinforcenh[.]shop reliabledmwqj[.]shop Musclefarelongea[.]pw Forbidstow[.]site gutterydhowi[.]shop Fanlumpactiras[.]pw Computeryrati[.]site Contemteny[.]site Ownerbuffersuperw[.]pw Seallysl[.]site Dilemmadu[.]site Freckletropsao[.]pw Opposezmny[.]site Faulteyotk[.]site Hemispheredodnkkl[.]pw Goalyfeastz[.]site Authorizev[.]site ghostreedmnu[.]shop Servicedny[.]site blast-hubs[.]com offensivedzvju[.]shop friendseforever[.]help blastikcn[.]com vozmeatillu[.]shop shiningrstars[.]help penetratebatt[.]pw drawzhotdog[.]shop mercharena[.]biz pasteflawwed[.]world generalmills[.]pro citywand[.]live hoyoverse[.]blog nestlecompany[.]pro esccapewz[.]run dsfljsdfjewf[.]info naturewsounds[.]help travewlio[.]shop decreaserid[.]world stormlegue[.]com touvrlane[.]bet governoagoal[.]pw paleboreei[.]biz calmingtefxtures[.]run foresctwhispers[.]top tracnquilforest[.]life sighbtseeing[.]shop advennture[.]top collapimga[.]fun holidamyup[.]today pepperiop[.]digital seizedsentec[.]online triplooqp[.]world easyfwdr[.]digital strawpeasaen[.]fun xayfarer[.]live jrxsafer[.]top quietswtreams[.]life oreheatq[.]live plantainklj[.]run starrynsightsky[.]icu castmaxw[.]run puerrogfh[.]live earthsymphzony[.]today weldorae[.]digital quavabvc[.]top citydisco[.]bet steelixr[.]live furthert[.]run featureccus[.]shop smeltingt[.]run targett[.]top mrodularmall[.]top ferromny[.]digital ywmedici[.]top jowinjoinery[.]icu rodformi[.]run legenassedk[.]top htardwarehu[.]icu metalsyo[.]digital ironloxp[.]live cjlaspcorne[.]icu navstarx[.]shop bugildbett[.]top latchclan[.]shop spacedbv[.]world starcloc[.]bet rambutanvcx[.]run galxnetb[.]today pomelohgj[.]top scenarisacri[.]top jawdedmirror[.]run changeaie[.]top lonfgshadow[.]live liftally[.]top nighetwhisper[.]top salaccgfa[.]top zestmodp[.]top owlflright[.]digital clarmodq[.]top piratetwrath[.]run hemispherexz[.]top quilltayle[.]live equatorf[.]run latitudert[.]live longitudde[.]digital climatologfy[.]top starofliught[.]top MITRE ATT&CK Tactics and Techniques See Table 8 through Table 13 for all referenced threat actor tactics and techniques in this advisory. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool . Table 8. Initial Access Technique Title ID Use Phishing T1566 Threat actors delivered LummaC2 malware through phishing emails. Phishing: Spearphishing Attachment T1566.001 Threat actors used spearphishing attachments to deploy LummaC2 malware payloads. Phishing: Spearphishing Link T1566.002 Threat actors used spearphishing hyperlinks to deploy LummaC2 malware payloads. Table 9. Defense Evasion Technique Title ID Use Obfuscated Files or Information T1027 Threat actors obfuscated the malware to bypass standard cybersecurity measures designed to flag common phishing attempts or drive-by downloads. Masquerading T1036 Threat actors delivered LummaC2 malware via spoofed software. Deobfuscate/Decode Files or Information T1140 Threat actors used LummaC2 malware to decrypt its callback C2 domains. Table 10. Discovery Technique Title ID Use Query Registry T1012 Threat actors used LummaC2 malware to query the user’s name and computer name utilizing the APIs GetUserNameW and GetComputerNameW. Browser Information Discovery T1217 Threat actors used LummaC2 malware to steal browser data. Table 11. Collection Technique Title ID Use Automated Collection T1119 LummaC2 malware has automated collection of various information including cryptocurrency wallet details. Table 12. Command and Control Technique Title ID Use Application Layer Protocol: Web Protocols T1071.001 Threat actors used LummaC2 malware to attempt POST requests. Ingress Tool Transfer T1105 Threat actors used LummaC2 malware to transfer a remote file to compromised systems. Table 13. Exfiltration Technique Title ID Use Exfiltration TA0010 Threat actors used LummaC2 malware to exfiltrate sensitive user information, including traditional credentials, cryptocurrency wallets, browser extensions, and MFA details without immediate detection. Native API T1106 Threat actors used LummaC2 malware to download files with native OS APIs. Mitigations The FBI and CISA recommend organizations implement the mitigations below to reduce the risk of compromise by LummaC2 malware. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s CPGs webpage for more information on the CPGs, including additional recommended baseline protections. These mitigations apply to all critical infrastructure organizations. Separate User and Privileged Accounts:  Allow only necessary users and applications access to the registry [ CPG 2.E ]. Monitor and detect suspicious behavior  during exploitation [ CPG 3.A ]. Monitor and detect suspicious behavior, creation and termination events, and unusual and unexpected processes running. Monitor API calls that may attempt to retrieve system information. Analyze behavior patterns from process activities to identify anomalies. For more information, visit CISA’s guidance on:  Enhanced Visibility and Hardening Guidance for Communications Infrastructure . Implement application controls to manage and control execution of software, including allowlisting remote access programs. Application controls should prevent installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlisting solution will block any unlisted application execution. Allowlisting is important because antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation. Protect against threat actor phishing campaigns by implementing CISA’s  Phishing Guidance and  Phishing-resistant multifactor authentication . [ CPG 2.H ] Log Collection: Regularly monitoring and reviewing registry changes and access logs can support detection of LummaC2 malware [ CPG 2.T ]. Implement authentication, authorization, and accounting (AAA)  systems [ M1018 ] to limit actions users can perform and review logs of user actions to detect unauthorized use and abuse. Apply principles of least privilege to user accounts and groups, allowing only the performance of authorized actions. Audit user accounts and revoke credentials for departing employees, removing those that are inactive or unnecessary on a routine basis [ CPG 2.D ]. Limit the ability for user accounts to create additional accounts. Keep systems up to date  with regular updates, patches, hot fixes, and service packs that may minimize vulnerabilities. Learn more by visiting CISA’s webpage:  Secure our World Update Software . Secure network devices  to restrict command line access. Learn more about defending against the malicious use of remote access software by visiting CISA’s  Guide to Securing Remote Access Software . Use segmentation to prevent access to sensitive systems and information, possibly with the use of Demilitarized Zone (DMZ) or virtual private cloud (VPC) instances to isolate systems [ CPG 2.F ]. Monitor and detect API usage, looking for unusual or malicious behavior. Validate Security Controls In addition to applying mitigations, the FBI and CISA recommend exercising, testing, and validating your organization’s security program against threat behaviors mapped to the MITRE ATT&CK Matrix for Enterprise framework in this advisory. The FBI and CISA recommend testing your existing security controls inventory to assess performance against the ATT&CK techniques described in this advisory. To get started: Select an ATT&CK technique described in this advisory (see Table 8 through Table 13 ). Align your security technologies against the technique. Test your technologies against the technique. Analyze your detection and prevention technologies’ performance. Repeat the process for all security technologies to obtain a set of comprehensive performance data. Tune your security program, including people, processes, and technologies, based on the data generated by this process. The FBI and CISA recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory. Reporting Your organization has no obligation to respond or provide information to the FBI in response to this joint advisory. If, after reviewing the information provided, your organization decides to provide information to the FBI, reporting must be consistent with applicable state and federal laws. The FBI is interested in any information that can be shared, to include the status and scope of infection, estimated loss, date of infection, date detected, initial attack vector, and host- and network-based indicators. To report information, please contact the FBI’s Internet Crime Complaint Center (IC3), your local FBI field office , or CISA’s 24/7 Operations Center at report@cisa.gov or (888) 282-0870. Disclaimer The information in this report is being provided “as is” for informational purposes only. The FBI and CISA do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favor by the FBI and CISA. Acknowledgements ReliaQuest contributed to this advisory. Version History May 21, 2025: Initial version.