Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fc35764235a06d5f…

MALICIOUS

RTF / .DOC

11.4 KB First seen: 2022-03-30
MD5: 594689313541eba99609b5ec2d8094a6 SHA-1: 139b934175a8b7ed96a2b8460f85ed9e055422a8 SHA-256: fc35764235a06d5f5606c30928486751361e0c14e068f76dfebc7eeb9dfda786
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The RTF file contains OLE object data and specifically triggers the CVE-2017-11882 vulnerability through the Equation Editor. This indicates an attempt to exploit a known vulnerability for code execution. No document body text or scripts were extracted, but the heuristics strongly suggest exploitation of CVE-2017-11882.

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_off00001e15.bin
69e5e96290a0301b25d820a53df6ee10cb6967db12241ba37d7c29067fd10bee
rtf-objdata-decoded RTF \objdata at offset 0x1E15 1835 bytes