Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 328ee8309ab7e1fd…

MALICIOUS

RTF / .DOC

5.2 KB First seen: 2022-08-17
MD5: cb050f112b3fb0075c6559a1edfea279 SHA-1: b498e1cb93be08986d9d9902f9fb517434d81c8d SHA-256: 328ee8309ab7e1fdf22eb20ddc6cbcab302790ff1e0ce7ec3a91fcf6422ce5a3
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains embedded OLE objects, specifically triggering the CVE-2017-11882 vulnerability related to Equation Editor. This exploit allows for the execution of arbitrary code, indicating a malicious intent to compromise the system. No specific malware family was identified, but the exploit method is clear.

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_off00000073.bin
85d9cc0a7842864f620bef87549781c3e89a96cbedaa06b4da2ca668d22cada9
rtf-objdata-decoded RTF \objdata at offset 0x73 2295 bytes