Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 828c15d94722cb54…

MALICIOUS

RTF / .DOC

5.67 MB
MD5: 6a189d7a893a37769edfb5b87b23743f SHA-1: f8ad8ce3c3d71d92e3b68f1c8fd9c19fd17cab69 SHA-256: 828c15d94722cb54496ea5305b792b2cdca80134121af96b0c65a2f5f72aaad2
222 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. The presence of ".objdata" sections and excessive hex data further indicates the hiding of a payload. The ".objupdate" directive suggests automatic activation of the OLE object, leading to the exploitation of the vulnerability and execution of the embedded malicious content.

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.
  • \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 ~5943KB 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
  • 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_off0000134c.bin
f9d7826b8b787436b9525f0e34b79bacc4404de95f4971d96e7d71948c658db5
rtf-objdata-decoded RTF \objdata at offset 0x134C 2971648 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.