Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ee466d9367bdbff9…

MALICIOUS

RTF / .DOC

30.4 KB First seen: 2022-12-05
MD5: 56f1ba7f47eacd4596a902dfeed92e6c SHA-1: 692df15e3007a08e0c0d997477245bcf9f4d2ea8 SHA-256: ee466d9367bdbff902155c39111dab267fd5facee126f44f749616811f8cdf14
220 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 a malformed Equation Editor object, which is a known exploit for CVE-2017-11882. The document body contains a lure instructing the user to 'Enable editing', indicating a social engineering attempt to bypass macro security. The presence of the Equation Editor exploit suggests the document is designed to download and execute a second-stage 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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
  • 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_off00005a56.bin
6ee9364a258ac91d1174657e2958c0e7255030bd31bedde34ffe756925de980e		 rtf-objdata-decoded RTF \objdata at offset 0x5A56 1794 bytes

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