Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ffc735ea518844e8…

MALICIOUS

RTF / .DOC

93.0 KB First seen: 2023-01-19
MD5: 61d2c8cd833864f38f10f11fc64cc8c1 SHA-1: 9e3203e92bf723df78fa35730ecfaf7f2694132a SHA-256: ffc735ea518844e8fb5276905b5368a23f9953ee18c235c51aebf9553dc2974f
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1059.005 PowerShell

The sample is an RTF document exploiting the CVE-2017-11882 vulnerability in the Microsoft Equation Editor. The document body attempts to lure the user into enabling editing by presenting academic content, which is a common tactic for macro-based malware delivery. The exploit targets the Equation Editor component, which is known to be vulnerable and can lead to arbitrary code execution.

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_off0000414d.bin
a8584df45386142e17ca9d4415b91e100d508a9b695c209b7775c7fd2ae66373		 rtf-objdata-decoded RTF \objdata at offset 0x414D 1539 bytes

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