Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 326f70eeb300f6c8…

MALICIOUS

RTF / .DOC

3.7 KB
MD5: 7c4eda298047f143381a724988b9a05f SHA-1: 49c8183d92ad3d9813d1d24e3655bda6c4bfc3ed SHA-256: 326f70eeb300f6c8f97700495a229ea9311aa344fdaea924a9ae5751a31c77ab
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 object data, specifically triggering the Equation Editor vulnerability (CVE-2017-11882). The presence of ".objdata" and ".objupdate" directives, along with the critical RTF_EQUATION_EDITOR heuristic, strongly indicates exploitation of this known Microsoft Office vulnerability. This technique is commonly used to deliver 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_off00000075.bin
f5fd292eec27d23a0d5011906344559a9baf64e1e015b63cbcae73a791a858ba
rtf-objdata-decoded RTF \objdata at offset 0x75 1574 bytes