Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e5b28a93a002f218…

MALICIOUS

RTF / .DOC

26.1 KB
MD5: 213572cfc656f2c17dccff8fff52f0b7 SHA-1: acad64bd3eebaddba0f842929742c49ca523ecd0 SHA-256: e5b28a93a002f218c3d4987afd538f1b7d000e365b34c21708a60bc0dedc3ce3
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE objects, specifically triggering heuristics related to Equation Editor. The critical firing 'RTF_EQUATION_EDITOR' and high firing 'CVE_2017_11882_ACTIVATION_RELATED' strongly indicate the exploitation of the CVE-2017-11882 vulnerability. This vulnerability allows for arbitrary code execution when the embedded Equation Editor object is activated, likely leading to the download and execution of a secondary 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_off00001b1d.bin
8a44cd29b886df5fdca9ec808f307130e023a450701e5e1703f8ee9c879a6444		 rtf-objdata-decoded RTF \objdata at offset 0x1B1D 1884 bytes

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