Malicious RTF — malware analysis report

Static analysis result for SHA-256 1edb1614b57ebd45…

MALICIOUS

RTF

8.1 KB First seen: 2019-08-04
MD5: db6257666c2b9dd6c28a92bd73d40832 SHA-1: 59b422c6083730a351050cf3364b3498f7c280d0 SHA-256: 1edb1614b57ebd45e6e69a60ef5ea8e8bae30f90954731ae11ae3aff8cafbdc3
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data and specifically triggers heuristics related to Equation Editor and CVE-2017-11882. This indicates the file is designed to exploit this known vulnerability for client-side code execution. The presence of the ".objupdate" directive further suggests an attempt to activate the embedded OLE object, likely to trigger the exploit. No specific family could be identified, but the exploit vector is clear.

Heuristics 5

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4133 bytes
SHA-256: c1f23ab4a9b8275bd63e987ecb8017e53ffd3fde2cbc1b58fb36549b0c8357f8