Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 111d4700a9dfd083…

MALICIOUS

RTF / .DOC

28.8 KB First seen: 2022-11-08
MD5: 2d49f4c06c0edb15b6107b34c1458c06 SHA-1: 75de347b194ad901883e4fa71b2382b6c7b54d8a SHA-256: 111d4700a9dfd0832610b6532472137367a764b4cc1538cb9240ab3a286c45f5
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 specifically identified as related to the Equation Editor vulnerability (CVE-2017-11882). The presence of \objupdate indicates an attempt to force OLE activation, and the document body includes a lure to 'Enable editing'. This strongly suggests the document is designed to exploit this known vulnerability to execute arbitrary code, likely a downloader for a secondary stage.

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_off00005a45.bin
ad4be8b75ef2a6d778c5a617afbbabf7b2d6a7359053d1696412b8bd43805055		 rtf-objdata-decoded RTF \objdata at offset 0x5A45 1814 bytes

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