Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f5c703840e569755…

MALICIOUS

RTF / .DOC

12.0 KB First seen: 2022-06-20
MD5: 7811cfd2b10e5d1ea11e19265a0f6971 SHA-1: 7dd04a095c4c7758402a3ca862840d9de5919598 SHA-256: f5c703840e56975516f462675df6a4f1fd97fc04f4e0bd2088066803110c137b
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains embedded OLE objects, specifically triggering the CVE-2017-11882 vulnerability through an Equation Editor exploit. This technique is commonly used to execute arbitrary code, likely to download and run a subsequent malicious payload. The document body content appears to be a list of items, possibly a lure, but the primary malicious activity is driven by the embedded exploit.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • \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_off00001db8.bin
13046835bcc1895cc36f91fdd15402bb25f5e726d5614f5214ba07289349df79		 rtf-objdata-decoded RTF \objdata at offset 0x1DB8 1366 bytes

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