Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6b14d392cea620dd…

MALICIOUS

RTF / .DOC

97.1 KB First seen: 2022-11-03
MD5: e05955ae5bc9af8a6ad95fc760dcbacd SHA-1: fb8fb13b384fb38962d32258251ce6ff50f4286f SHA-256: 6b14d392cea620dd598002091785f43d484ea752bd2efb71a832751dedd9cda3
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) for execution. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics strongly indicates exploitation of this known vulnerability. The `RTF_OBJUPDATE` heuristic suggests that the embedded OLE object is automatically activated upon opening the document, leading to the execution of the exploit. No document body text or scripts were extracted, but the exploit itself is sufficient to classify the attack pattern.

Heuristics 5

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001e2a.bin
2f62246769452a7e0279029953f1a0ca3b8f9ab60fe0782484a7e1dd0ddebc12		 rtf-objdata-decoded RTF \objdata at offset 0x1E2A 1876 bytes

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