• LeetMX - a Yearlong Cyber-Attack Campaign Against Targets in Latin America

    leetMX is a widespread cyber-attack campaign originating from Mexico and focused on targets in Mexico, El Salvador, and other countries in Latin America, such as Guatemala, Argentina and Costa Rica. It has been operating since November 2016 at least. We are uncertain of its objectives but estimate it is  criminally motivated.

    leetMX infrastructure includes 27 hosts and domains used for malware delivery or for command and control.  Hundreds of malware samples have been used, most are Remote Access Trojans and keyloggers.

    Interestingly, the attackers camouflage one of their delivery domains by redirecting visitors to El Universal, a major Mexican newspaper.


    Below are samples of malicious Office documents delivered to targets. These documents contain macros that run PowerShell, which downloads and run various payloads from domains and hosts controlled by the attackers.

    Ministerio de Hacienda El Salvador – Declaraciones Pendientes folio 34598.docm

    Ministerio de Hacienda SV Folio de Aclaracion SVMH2054983.docm

    Buro de Credito – Reporte Especial Folio de Operacion 438346982.doc

    Estimado Cliente.
    Su pedido ha sido verificado y aprobado por su banco. Conserve este número de folio para cualquier trámite como Cambios y Cancelaciones B0987525347.
    Puede Imprimir este documento para su referencia.
    Institución de Banca Múltiple

    SATMX-Folio 46565.xls

    Servicio de Administracion Tributaria SAT Declaraciones Pendientes Folio de Consulta 45817089.xls

    Other documents used as malware droppers are:

    • buro de credito reporte de movimientos recientes folio de operacion 3590543.doc  (b39076ed23aa7c251aee89701f084117)
    • buro de credito reporte de movimientos acreditados folio 45665.doc (783e4c2eeeb69f058b30c5b697bfa6be)
    • ministerio de hacienda el salvador consulta de estado de cuenta moroso folio (7a769d5e7401a1b858e58fea1144cb6b)
    • buro de credito reporte de nuevos cargos folio 273534.doc (0b8f4e79df43b951380938bdc380f53a)
    • Buro de Credito Afilicion de Cargo Automatico Registrado BMX46948964.doc (8f963a7e26a29b4ba2cae9eb11b137d7)
    • Buro de Credito Folio de Aprobacion de Nuevos Creditos 593783.xls (4e12eeb78cebaf091cdf26b46a816931)
    • Buro de Credito – Folio de Afilicion a Cargo Automatico 3274398BMX.doc (fe6b1f263e10f305af2eba10a8af6ba1)
    • Buro de Credito – Folio de Afilicion a Cargo Automatico 3274398BMX.doc (6c5d24a054ab952ea1983e7b663474ce)

    Below is an example of a malicious PowerShell code in one of the documents:


    The domains and hosts below are all part of the malicious infrastructure, and are used for malware delivery or for command and control.


    Mexican origins

    Multiple parts of the malicious infrastructure indicate that the attackers are based in Mexico, as depicted in the Maltego graph below. (However, the reader should remember that these are only technical indicators and could all be forged).

    • Dynamic DNS hosts used for command and control were allocated IPs by Mexican internet services providers. For example, c0pywins.is-not-certified[.]com has been allocated addresses by AS8151 Uninet S.A. de C.V., MX, as can be seen in PassiveTotal:

    • Malware delivery domain rsafinderfirewall[.]com redirects to El Universal, a major Mexican newspaper, when visited without the file-path of the malware (such as rsafinderfirewall[.]com/Es3tC0deR3name.exe):

    • Physical address in Mexico in multiple domains Whois data:

    Registrant Name: hector jesus herrera duron
    Registrant Organization: motogplus
    Registrant Street: c 29 no 300
    Registrant City: merida
    Registrant State/Province: Chiapas
    Registrant Postal Code: 97000
    Registrant Country: MX
    Registrant Phone: +52.9991062881

    • Attacker IP address in Mexico. In one targeting at least, the attackers used a URL shortening services that publicly displays the IP address of anyone who clicked the shorted URL.  The first click – likely the attacker testing the link before spreading it to victims – came from , which belongs to Mexican ISP Cablemas Telecomunicaciones:

    In this incident mostly Mexicans were targeted, as can be seen in the table below:

    Country URL clicks
    Mexico 343
    United States 79
    El Salvador 67
    other 53

    Leet filenames

    The attackers often use leetspeak alphabet in malware filenames. Below is a list of malware filenames converted from leet to plain English (via Universal Leet (L337, L33T, 1337) Converter):

    Original filename Conversion from Leet
    Ad0v3upd4t3s2o17.exe Adoveupdates2017.exe
    0ff1ceval1dKey001[1].exe officevalidKeyooi[i].exe
    AFDsajgeoi.exe AFDsajgeoi.exe
    Ad0v31ns5t411.exe Adoveinsstaii.exe
    Off1c3764.exe Officetga.exe
    ad0v3upd4t3s2o16[1].exe adoveupdates2016[i].exe
    sqlwriter.exe sqlwriter.exe
    Off1cc3k3ysV4l1d.exe OfficceKeysValid.exe
    CudaUtil.exe CudaUtil.exe
    Javaupdate2017205.exe Javaupdate201705.exe
    USB Flash Security.exe USB Flash Security.exe
    J4v4S3tups00.exe JavaSetupsoo.exe
    ad0veupdates2o17.exe adoveupdates2017.exe
    0ff1c3v4l1dkey2017.exe officevalidkey2017.exe
    Ad0v31n5t411.exe Adoveinstaii.exe
    Off1c3v4l1dK3y2017s[1].exe OfficevalidKey2017s[i].exe
    Javatmp2539891.exe Javatmp2539891.exe
    AVGPDTER465.exe AVGPDTER465.exe
    K3y2017s.exe Key2017.exe
    hp.exe hp.exe
    Off1c3v4l1dK3y2017s.exe OfficevalidKey2017.exe
    Off1cc3k3yV4l1ds.exe OfficcekeyValids.exe
    javaupdates2017.exe javaupdates2017.exe
    Serial IO.exe Serial IO.exe
    0ff1ceval1dKey001.exe officevalidKey001.exe
    J4v4upd4t352017s.exe Javaupdates2017s.exe
    Jav4upd4t3r4ds.exe JavaUpdaterads.exe
    Ad0vs365489.exe Adovs365489.exe
    Off1cc3s4dd0ns.exe OfficcesAddons.exe
    gbrgeidf.exe gbrgeidf.exe
    oct04.exe.exe octoa.exe.exe
    Off1c3TMP2018.exe OfficeTMP2018.exe
    IconToolkit.exe IconToolkit.exe
    Ad0v365489.exe Adovegsa89.exe
    Es3tC0deR3name.exe EsetCodeRename.exe
    J4v4S3tup00.exe JavaSetupoo.exe
    J4v4465632.exe Java465632.exe
    j4v4updat3s2016.exe javaupdates2016.exe
    AVGF1rr3w4ll.exe AVGFirrewall.exe
    J4v4mxfullv3rsion.exe Javamxfullversion.exe
    0fficeV4lids00.exe officeValidsoo.exe


    More then 550 samples used in this campaign are available on VirusTotal. Most of them are Xtreme RAT variants (a short analysis by Sophos is available – Troj/Xrat-R , a PCAP is available in pcapanalysis.com) and iSpy Keylogger.

    Indicators of compromise

    Indicators of compromise are available for subscribers of the ClearSky threat intelligence service in MISP event number 249. Indicators are also available in the following CSV file: LeetMX-indicators.csv and on PassiveTotal.

    Key parts of the infrastructure are depicted in the Maltego graph below (click to enlarge):