Malicious RTF — malware analysis report

Static analysis result for SHA-256 21d5aec3ad67d50d…

MALICIOUS

RTF

233.8 KB First seen: 2019-05-31
MD5: e1a88dfaae33c91c94e9e1977c07125f SHA-1: 15580778fac31674f580af1fe8c70cc2f859ae80 SHA-256: 21d5aec3ad67d50dbb831ca6e15341a631c0e01e79ab95b247458edc53f86a93
220 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 Microsoft Equation Editor, which is known to allow for arbitrary code execution. This exploit is typically delivered via spearphishing attachments.

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.
  • 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_off0000003f.bin rtf-objdata-decoded RTF \objdata at offset 0x3F 3627 bytes
SHA-256: 35053c5b7765d7e3ff24d72bda610bada9a64bb53e9d33cb74c6d9c6e0089b00