Rtf.Downloader.CVE_2017-6336326-3 — RTF malware analysis

Static analysis result for SHA-256 f5be5f70ab3332e3…

MALICIOUS

RTF

4.10 MB Created: 2017-12-31 01:52:00 First seen: 2018-01-08
MD5: cafd0241dc260feac5438c21d4c4168d SHA-1: f5d9e4e4c90ffde97bc5c8ae4be97c5b1bba41f8 SHA-256: f5be5f70ab3332e3c45d79f93cb1ea0cda54bebbed628fabca7fe73c8cc50f3f
362 Risk Score

Malware Insights

Rtf.Downloader.CVE_2017-6336326-3 · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is an RTF document that contains OLE object data and triggers the CVE-2017-8759 vulnerability. This vulnerability is known to be used for downloading and executing malicious payloads. The embedded URL http://37.230.113.36/t.php?stats=send&thread=0 is highly suspicious and likely serves as the distribution point for the second-stage malware. ClamAV also detected this file as Rtf.Downloader.CVE_2017-6336326-3.

Heuristics 10

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • ClamAV: Rtf.Downloader.CVE_2017-6336326-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Downloader.CVE_2017-6336326-3
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • INCLUDETEXT/INCLUDEPICTURE remote URL high RTF_INCLUDE_REMOTE
    RTF document uses INCLUDETEXT or INCLUDEPICTURE with an http:// URL — Word can fetch the remote content on open depending on Office version and external-content settings, enabling remote template injection, NTLM capture via redirects, or payload delivery
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://37.230.113.36/t.php?stats=send&thread=0 In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000c568.bin rtf-objdata-decoded RTF \objdata at offset 0xC568 2598 bytes
SHA-256: 70f8d348a8537c8d35bff34924ff63bfd43c7cbeeac91b357bbb2e27ed8abfc0
objdata_01_off0000dc96.bin rtf-objdata-decoded RTF \objdata at offset 0xDC96 2723 bytes
SHA-256: a41915f445d2a4fc02225c10cdec98e056d124678bb1d2a14e50ca01a4ff7fb3

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