Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 70682865de94ea5a…

MALICIOUS

RTF / .DOC

83.8 KB First seen: 2023-01-19
MD5: b902d6b03409aef34a8fb5124d5d251a SHA-1: acf5ca6072b0e36b7978e38af214e333a7b89a76 SHA-256: 70682865de94ea5aaa3b2d66d6e491be535a2337d6f0be50271169f6ff3cbd70
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

The sample is an RTF document that contains an embedded OLE object specifically identified as related to CVE-2017-11882, exploiting the Equation Editor vulnerability. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. The embedded object is likely designed to execute a malicious payload upon activation.

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_off0000511d.bin
f80183752b6e682949af7447dd3f6a7ee85320055c4b684292058186533794a6		 rtf-objdata-decoded RTF \objdata at offset 0x511D 1675 bytes

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