Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 31799a1fa82ec2ad…

MALICIOUS

RTF / .DOC

27.4 KB First seen: 2022-11-18
MD5: db91f679709710d385f0838760b6445f SHA-1: 6006ab6e61fbb9c1db2a7541ec24cb57b0deb63d SHA-256: 31799a1fa82ec2adee55cdae03ccc83cbd5f0ab731c9df0b3aa450d8b508ca3e
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell

The sample is an RTF document containing an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. The heuristic firings indicate that the document is designed to trigger this exploit, which typically leads to the execution of a secondary payload. The document body contains a lure related to marketing strategy, likely to trick the user into enabling editing or macros.

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_off000054cb.bin
cb182626d2860ce0c798f748b7bd8f5ffe9866a747a4c067eb0399044a2b05bf		 rtf-objdata-decoded RTF \objdata at offset 0x54CB 1406 bytes

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