Malicious RTF — malware analysis report

Static analysis result for SHA-256 c88b5a07c73a4fca…

MALICIOUS

RTF

7.2 KB First seen: 2019-08-04
MD5: ad434176a012a876d243ff0331ebe0f6 SHA-1: 4be75d6ee518cedb1d177a06729533471121c875 SHA-256: c88b5a07c73a4fca76dd3959b3095321ee2083d131520e34afb152a827d56dea
240 Risk Score

Malware Insights

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

The sample is an RTF document that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for arbitrary code execution when the document is opened. The presence of OLE object data and the specific Equation Editor CLSID firing strongly indicate this exploit. The file is classified as malicious and likely delivered via spearphishing.

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_off0000003c.bin rtf-objdata-decoded RTF \objdata at offset 0x3C 3641 bytes
SHA-256: e5bb5548a06fb2a8875d8f2e19eff8b45ad7f81ba4d9ba7498f5351582d66425