Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f6a8163b680a0e66…

MALICIOUS

RTF / .DOC

585.5 KB
MD5: 13ee91bb32b8af90f1a168cb75a6110a SHA-1: 5a5b86b1c6934acd760f38a873030a6ef3a5ccaa SHA-256: f6a8163b680a0e66e368319d353a9b6f5bd83ecdabc2299e51b1881fe688f204
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in the Microsoft Equation Editor. This vulnerability allows for the execution of arbitrary code by embedding a malicious OLE object. The extracted artifact 'objdata_00_off00000047.bin' is the decoded payload from this object, which is highly indicative of a second-stage execution attempt.

Heuristics 6

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • 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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000047.bin
f10e5906c87000a69d98c46b3e31b6bb8e85f0bcd280b9d2f2cde9451c24c52b
rtf-objdata-decoded RTF \objdata at offset 0x47 299679 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.