Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1ec35958e0005a3e…

MALICIOUS

RTF / .DOC

1.66 MB First seen: 2023-08-24
MD5: 12ed0417db74bb3a26ff33e0102c7e0d SHA-1: d22e2341ae648d0f93c69ded04076c7e01308689 SHA-256: 1ec35958e0005a3ef9083f86baaab2877a2260fb19af3050845dfd9a529a5d5f
222 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Phishing: Spearphishing Attachment

The RTF document contains an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This vulnerability is known to be used to execute arbitrary code, typically to download and run a second-stage payload. The presence of a PE file within the OLE object data strongly suggests the delivery of a malicious executable.

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.
  • Decoded Equation Editor payload + PE critical 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.
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1745KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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_off00000090.bin
70d24f08653460d4ca9f31df4e21f9e091acdb4502520524d0731c423296adef
rtf-objdata-decoded RTF \objdata at offset 0x90 872534 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.