Malicious RTF — malware analysis report

Static analysis result for SHA-256 f25b8ed28534f688…

MALICIOUS

RTF

261.2 KB Created: 2018-07-03 09:28:00 First seen: 2019-02-20
MD5: 0037e8c9f77d4fb986a2bc9d21422073 SHA-1: b37da33428a62ec3eb90546bb0bcb4656b6f39df SHA-256: f25b8ed28534f688392da222a5ec06844d5ae9ca667e7fc97cedbd4034e54603
262 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains critical heuristic firings for CVE-2017-11882 and CVE-2017-8759, indicating exploitation of these vulnerabilities. It also contains an embedded OLE object that is updated, suggesting it's designed to execute code. The presence of an unknown URL further supports the likelihood of it downloading a secondary payload, consistent with a dropper.

Heuristics 7

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • 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.Dropper.Agent-6845271-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-6845271-0
  • \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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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 https://lotusconstructiontl.com/wp-content/uploads/crt.msi In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000bf6b.bin rtf-objdata-decoded RTF \objdata at offset 0xBF6B 15672 bytes
SHA-256: c68e12e50549fa89f521902488689aae39fbfa45cabaf0ac8b48467a59332edb

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