Malicious RTF — malware analysis report

Static analysis result for SHA-256 9ac09ea38c9cf11c…

MALICIOUS

RTF

252.2 KB Created: 2018-06-13 14:44:00 Authoring application: WPS Office \'b8\'f6\'c8\'cb\'b0\'e6 First seen: 2019-02-26
MD5: b712bea585d223ab92efff4aa977396b SHA-1: c3bec0bbd94e903cc7a6b310ef04177ebc2603f3 SHA-256: 9ac09ea38c9cf11ca13a2c3dbdcfbe0fe4a15cb609be451f7159ecebdd20d311
282 Risk Score

Malware Insights

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

The RTF file contains embedded OLE objects and specifically triggers heuristics related to Equation Editor vulnerabilities, including CVE-2017-11882 and CVE-2018-0802. This indicates the file is designed to exploit these vulnerabilities for client-side code execution, likely delivered as a spearphishing attachment.

Heuristics 8

  • 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: Rtf.Exploit.CVE_2018_0802-6825822-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2018_0802-6825822-0
  • \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.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00008208.bin rtf-objdata-decoded RTF \objdata at offset 0x8208 102640 bytes
SHA-256: a7b0325839e6f26bb9088626d5fb9d50808d83367d640febee23389daaea99e0
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off0003a41e.bin rtf-objdata-decoded RTF \objdata at offset 0x3A41E 9784 bytes
SHA-256: ab74bc137898ac0b0f0ca24831d2bc10f79add120593e5f2ac6da4b624d91759
objdata_02_off0003a430.bin rtf-objdata-decoded RTF \objdata at offset 0x3A430 35 bytes
SHA-256: 1188b98b21f50564ab8b476f25b6deab999a2f58a56c4dd0daa0f5883cfa941d

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