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
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):

Article Link: http://www.clearskysec.com/leetmx/