Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 034567b36fbd495c…

MALICIOUS

RTF / .DOC

4.44 MB First seen: 2022-07-31
MD5: 45c738001216ca2356874e410fd8da8b SHA-1: 41934d677961383e376622d3aa192554bf8568c0 SHA-256: 034567b36fbd495c69884222afafcd59eb3b5f7ed6eecd7eb57be538b2bb7d74
242 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an embedded OLE object specifically related to the Equation Editor vulnerability (CVE-2017-11882). This exploit is designed to execute arbitrary code, likely to download and run a second-stage payload. The presence of large, high-entropy hex data within the OLE object further suggests it is used to hide a malicious executable.

Heuristics 7

  • 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.
  • \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 ~4657KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off0000007c.bin
1ee8983f21a4262d9f07aff7bfa0b30f2635518b847be18bb643c5bbc85dae19
rtf-objdata-decoded RTF \objdata at offset 0x7C 2329161 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.