Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0edd773875311776…

MALICIOUS

RTF / .DOC

42.4 KB First seen: 2023-01-23
MD5: 8ad8c615dab288132971594224aa8f4e SHA-1: dbd94f5775c44c674c2470e39e39bd60386b9740 SHA-256: 0edd773875311776998229b0609be9f287c37ca828b35f74c6c2f0cbdd99449f
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that contains embedded OLE object data, specifically related to Microsoft Equation Editor. High-confidence heuristics indicate exploitation of CVE-2017-11882, a known vulnerability in Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic to bypass macro security settings and trigger the exploit. The exploit likely leads to the download and execution of a second-stage payload.

Heuristics 6

  • 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.
  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00008f5f.bin
44017c4dbef7988951ebea421293f1a805e072066318d4d4b0087dffa65af2ca		 rtf-objdata-decoded RTF \objdata at offset 0x8F5F 1913 bytes

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