Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7f15957b24b641b3…

MALICIOUS

RTF / .DOC

33.9 KB First seen: 2022-12-23
MD5: 5d38e27ff1af10e2b864f0a068902db6 SHA-1: d5062ad5e3c3d511c18fb5a94f9801d117222bbd SHA-256: 7f15957b24b641b3c3f74821ce5fa9b5f4804ae4e0cdd01db0d4828153385878
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, likely to trick the user into enabling editing or macros. The embedded OLE object is designed to execute arbitrary code upon activation, which is a common technique for initial access and payload delivery.

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_off00005325.bin
22f124a831b288d817374189467f4c9bdad17c96bbeac63905ab883faeae1431		 rtf-objdata-decoded RTF \objdata at offset 0x5325 1451 bytes

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