Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 40360c9d908af1b8…

MALICIOUS

RTF / .DOC

22.8 KB
MD5: 324a8c804041f03a26706edbda8522df SHA-1: 25139b7412620ab52b0a84b8ba0a0d96dcf9a78f SHA-256: 40360c9d908af1b81ba2f5e912d6289075a32e320fad70c1b050a026d5ab26df
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model

The sample is an RTF document containing an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). The presence of ".objdata" and ".objupdate" sections, along with the specific ProgID "eqUAtIOn.3", strongly indicates exploitation of this known flaw. This technique is commonly used to achieve arbitrary code execution on the victim's machine.

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_off00001fe7.bin
178b7e1701268b095f96523a6a68f07b30e17983c111e413474acb1b18053fc0
rtf-objdata-decoded RTF \objdata at offset 0x1FE7 1816 bytes