Malicious RTF — malware analysis report

Static analysis result for SHA-256 c795a13148b13b6c…

MALICIOUS

RTF

1.83 MB Created: 2022-08-30 19:09:00 First seen: 2022-11-08
MD5: 43e2a8601a4f70897d73353c4908f224 SHA-1: f13aeba7926d6c29485509f7dac24a7fd623c2d4 SHA-256: c795a13148b13b6c293c11099fbe06aed8b478e1713d5c3c849fa7acabc215cc
182 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter T1059.001 Command and Scripting Interpreter: PowerShell

The RTF file contains embedded OLE object data and triggers an ".objupdate" command, indicating an attempt to activate the embedded object. Critical heuristic firings for CVE-2017-8759 confirm exploitation of MSXML SAX OLE activation. The excessive hex data within the OLE object likely hides a secondary payload. The embedded URL "http://ocsp.thawte.com0" is suspicious and may be used to download the payload.

Heuristics 6

  • 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.
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1709KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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 http://ocsp.thawte.com0
    • http://schemas.microsoft.com/office/word/2003/wordml

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00040f8a.bin
df0f1d3e20dadfaf5343bf4ac1b39e35cd4e79de902c5e2dc2854bc871960ff0		 rtf-objdata-decoded RTF \objdata at offset 0x40F8A 730447 bytes

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