Malicious RTF — malware analysis report

Static analysis result for SHA-256 1865286e44154b2a…

MALICIOUS

RTF

45.3 KB
MD5: 8171c34069b19f73cf25f1579c4b0cc2 SHA-1: be7fef378a5af1d38157854cdeb7c9618ebf3a32 SHA-256: 1865286e44154b2ae6c2763f2e7b08304618acc3d7346628314b64e2c99ecb9a
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains heuristics indicating the exploitation of CVE-2017-11882 via an embedded OLE object, specifically using the 'EQUaTIOn.3' ProgID. This exploit is known to facilitate the execution of arbitrary code, which is likely used here to download and run a secondary payload. The presence of ".\objupdate" further confirms the intent to activate the embedded object.

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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001ef9.bin
834bc768eeef9c6f2c9d0b1fab8f5fd6af7c8c7c44be1279d5a3156bc856a4d2		 rtf-objdata-decoded RTF \objdata at offset 0x1EF9 1833 bytes

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