Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 12433558ffa9e6f9…

MALICIOUS

RTF / .DOC

22.7 KB
MD5: a5ec472720904f464a5cd2d15b3c6036 SHA-1: 749b6c5b31ae1b3c761d4c37e11083d1614c4308 SHA-256: 12433558ffa9e6f9c5f1aed96d15733bf3df34cfe1f0df4c1c73ccdf80a178e6
180 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data, specifically triggering heuristics related to Equation Editor and CVE-2017-11882. The presence of `EqUaTiOn.3` as a ProgID strongly indicates exploitation of this known vulnerability. This technique allows for arbitrary code execution upon activation of the embedded object, likely leading to 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001e45.bin
2a15e894ddc37d4c0e7a7edba48e3421812476ee80d9cf7e507d5b0763c9dabc
rtf-objdata-decoded RTF \objdata at offset 0x1E45 1436 bytes