Malicious RTF — malware analysis report

Static analysis result for SHA-256 a944d5373aab3231…

MALICIOUS

RTF

8.1 KB First seen: 2018-10-19
MD5: e441239a13ee692584c7a1cd0104c5de SHA-1: 8dfd60ebf6450d20ad70b2524278b4c687dc77e8 SHA-256: a944d5373aab3231e88ac26c1d7f9fa150d9a0eaf0f1bd524d99989d4a888dd3
280 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object. Heuristics indicate a critical vulnerability, CVE-2017-11882, related to the Equation Editor component. This exploit allows for arbitrary code execution upon opening the document, likely delivered via spearphishing.

Heuristics 6

  • 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
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00000040.bin rtf-objdata-decoded RTF \objdata at offset 0x40 4135 bytes
SHA-256: 9e27450ee70469b0194694bd4abc7ae61d360dc51b9b7c91f8937640360874c1