Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 33267488a065cdb6…

MALICIOUS

RTF / .DOC

321.4 KB First seen: 2022-03-18
MD5: 63483560ffff1a2df9f1194b5f7288bc SHA-1: f2cf727e96bcb2b3be33d9891351e15f50fab700 SHA-256: 33267488a065cdb6e5d2ce3c143bfc7549634c26fabfef4e1ee622fda18886d9
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains embedded OLE objects and specifically triggers the CVE-2017-11882 vulnerability related to Microsoft Equation Editor. This indicates the document is designed to exploit this known vulnerability for arbitrary code execution upon opening. No scripts were extracted, but the exploit itself is the primary attack vector.

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_off00000079.bin
8c23bf1e1faf1529988ac7fa7bc659b7217685011b4aa614f7e171f222c1510b
rtf-objdata-decoded RTF \objdata at offset 0x79 108840 bytes