Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8d8f1000460a883a…

MALICIOUS

RTF / .DOC

34.8 KB First seen: 2022-12-13
MD5: c2d17cd040abb6441efaf09e77d7fb23 SHA-1: d13e4f68eb0e3c449a7bfa348590df84afb946a8 SHA-256: 8d8f1000460a883a5eed19e00f20549953e26206185c2c3de7597fa546bcdc08
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 strategy, instructing the user to 'Enable editing', which is a common technique to bypass macro security. The exploitation of CVE-2017-11882 is a critical finding, indicating the document's intent to execute arbitrary code.

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_off00005b91.bin
39aa457d005e93900ca7acdd0fc2ab8a0069401f7834680fb9964680bda49da0		 rtf-objdata-decoded RTF \objdata at offset 0x5B91 1748 bytes

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