Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5a31c77293af2920…

MALICIOUS

RTF / .DOC

11.5 KB
MD5: 05c137d8e79ce59ed6e4b7cd78e5b8a2 SHA-1: 3a41de3774b6a17a34a8bedf1a0881a3f08d492d SHA-256: 5a31c77293af2920d7020d5d0236691adcea2c57c2716658ce118a5cba9d4913
240 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit is known to allow for arbitrary code execution, typically used to download and run a second-stage payload. The presence of the Equation Editor CLSID and the specific CVE firing strongly indicate this attack vector.

Heuristics 5

  • 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.
  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • \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_off00000cb6.bin
83d4b43e93c12c74e5e858e293964017b49e06550f2ce81cbe7a6aa91581ce70
rtf-objdata-decoded RTF \objdata at offset 0xCB6 4150 bytes