Malicious RTF — malware analysis report

Static analysis result for SHA-256 722e5d3dcc8945f6…

MALICIOUS

RTF

492.2 KB Created: 2018-04-22 11:40:00 First seen: 2019-04-17
MD5: c56c50c7e98f717ce0138620fb30b2c0 SHA-1: 49ed5bfb838ba49d3c2a608b0be9497a256f3f51 SHA-256: 722e5d3dcc8945f69135dc381a15b5cad9723cd11f7ea20991a3ab867d9428c7
284 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of exploitation, specifically related to the Equation Editor and CVE-2017-11882. The presence of OLE object data and the explicit detection of CVE-2017_11882_ACTIVATION_RELATED and RTF_EQUATION_EDITOR heuristics strongly suggest this vulnerability is being leveraged. The document body, though partially in Russian and truncated, appears to be a lure related to document processing or delivery, consistent with a spearphishing attachment.

Heuristics 9

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • ClamAV: Doc.Exploit.Cve_2017_11882-7570663-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.Cve_2017_11882-7570663-1
  • \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.
  • Package object class high RTF_OBJCLASS_PACKAGE
    OLE Package object — can wrap arbitrary files
  • OLE object data medium RTF_OBJDATA
    RTF contains 3 \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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0001b1f4.bin rtf-objdata-decoded RTF \objdata at offset 0x1B1F4 186608 bytes
SHA-256: 081c399a68df734f16550b44b040e4b52d852577d4aa94580f3e2e5016120c1b
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off0007640a.bin rtf-objdata-decoded RTF \objdata at offset 0x7640A 9782 bytes
SHA-256: 7ba7465859c75f617584ec1f19332ec94c7c505d78a18bd4838e166d5af100af
objdata_02_off0007641c.bin rtf-objdata-decoded RTF \objdata at offset 0x7641C 35 bytes
SHA-256: 1188b98b21f50564ab8b476f25b6deab999a2f58a56c4dd0daa0f5883cfa941d

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