Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 279f526bb1ae2060…

MALICIOUS

RTF / .DOC

37.8 KB First seen: 2022-12-15
MD5: df8bdc4bd98cac7d713244e5006c0a8b SHA-1: ada6f67e071c7827912459cdbf645c1a97e4359b SHA-256: 279f526bb1ae20608965f03b3509ac9700543aa423e467da898a2004aeb39b4e
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The document body contains a lure related to marketing management, instructing the user to 'Enable editing' to view the content. The embedded OLE object is designed to be activated, likely to download and execute a secondary payload.

Heuristics 6

  • 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 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00008373.bin
87e32f8b60b31e82d1feecdb20aec7d8d4c5344ecec3c35609b97ee71a793d7d		 rtf-objdata-decoded RTF \objdata at offset 0x8373 1420 bytes

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