Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ebc2d0630778b668…

MALICIOUS

RTF / .DOC

1.96 MB First seen: 2022-02-15
MD5: 07a7cea5eab70c8af278afcf54ddd7b4 SHA-1: 2f94539993d4cb0f7f2b27a14de40f9105fb9244 SHA-256: ebc2d0630778b66881b1dbc0c87601b5fd166826a201ccd060911ea9af17815b
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains an embedded OLE object that leverages the Equation Editor, specifically triggering the CVE-2017-11882 vulnerability. This exploit allows for the execution of arbitrary code. The embedded object's ProgID 'Equation.3' is a strong indicator of this exploit. The decoded object data contains obfuscated VBScript-like code that appears to be designed to download and execute a second-stage payload.

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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001347.bin
812f3405867e20ccd0c9aa75ac00beed8c8760c704e0e410c09cf3983d8059f7		 rtf-objdata-decoded RTF \objdata at offset 0x1347 25617 bytes
objdata_01_off00019574.bin
689965aaaf88dfda2c46136e8ee45ccbdf5d380abcba88d5f9ff529d3c59ced2		 rtf-objdata-decoded RTF \objdata at offset 0x19574 463381 bytes

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