Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a8e8a068ad37fffa…

MALICIOUS

RTF / .DOC

3.1 KB
MD5: 7187e199ddefe203d8d25be24ec5faa5 SHA-1: 11dd9bf957419a4608ab086b4af6d7e86eb1aa0b SHA-256: a8e8a068ad37fffa43336ca0cc9f6aea938db591b91d22ffa61c97de2d4c3cc0
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object. Heuristics indicate the exploitation of CVE-2017-11882 via the Equation Editor. This vulnerability allows for the execution of arbitrary code when the embedded object is activated, likely leading to a second-stage payload download and execution.

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_off000000b2.bin
91aa671031901393ce6a8ea553464dfaeaa7e4722d7e2367687bdbb3b44c9b11
rtf-objdata-decoded RTF \objdata at offset 0xB2 1286 bytes