Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d1aa06640d63f6df…

MALICIOUS

RTF / .DOC

26.0 KB
MD5: d31be771a634a97eef5724dd38ccb1ab SHA-1: de491b5dfe0b242fd0326521729597d34533e8dd SHA-256: d1aa06640d63f6dfc3c236302767306358d6607453103ac8d1eefdb8235af3c8
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains embedded OLE objects, specifically triggering the CVE-2017-11882 vulnerability related to Equation Editor. The presence of ".objdata" and ".objupdate" sections, along with the "Equation Editor activation" heuristic, strongly indicates exploitation of this known Microsoft Office vulnerability. This technique is commonly used to deliver a second-stage payload.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001b44.bin
c876c7e972947350d09e1072e3ea5ed3634cbf9b316370389bace04a999dd34e		 rtf-objdata-decoded RTF \objdata at offset 0x1B44 1950 bytes

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