Malicious RTF — malware analysis report

Static analysis result for SHA-256 1edf58da7a1e1d1b…

MALICIOUS

RTF

194.2 KB First seen: 2020-02-04
MD5: 242accb2e22f3d9d69155bf6cc903bcf SHA-1: c49ff39964278b7219b7bc75f83ae5d634ac8a94 SHA-256: 1edf58da7a1e1d1b1d6503f2a5c50dfa4a7d7d8bfe44bde71c0bb924a6b29582
182 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that decodes to a PE file, leveraging the CVE-2017-11882 vulnerability in Equation Editor. This technique is commonly used to deliver a secondary payload, indicating a malicious document designed for exploitation.

Heuristics 5

  • Decoded Equation Editor payload + PE critical CVE likely RTF_EQUATION_EDITOR
    RTF decodes to an Equation Editor ProgID adjacent to OLE activation and the same decoded object stream contains embedded PE bytes. This matches the Equation Editor exploit surface used by CVE-2017-11882 / CVE-2018-0802 documents, while requiring payload evidence to avoid flagging benign Equation references.
  • 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.
  • \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_off0000006d.bin rtf-objdata-decoded RTF \objdata at offset 0x6D 99353 bytes
SHA-256: c86c5b533bbb514f969348e1f78eb77920bf273491b31e61ab92fea6f9084a82
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.