Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7a505bd8ef8dac73…

MALICIOUS

RTF / .DOC

31.4 KB First seen: 2022-12-06
MD5: 9d155fa6bcb36432c5f6d337e26a81e3 SHA-1: a1d05f136c5cdaca0a8b99d2c0dc736963df610f SHA-256: 7a505bd8ef8dac738671e61a7507851783d62cf1dd72332bea4a6e39aa48b98e
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The RTF document contains an embedded OLE object specifically identified as related to CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of \objupdate and \objdata sections, along with the critical RTF_EQUATION_EDITOR heuristic, strongly indicates an attempt to exploit this vulnerability. The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and facilitate the execution of the embedded exploit.

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.
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off0000578c.bin
23845aacd15b1a4ea63e25104c8634dc3127925d182572d91a07534fde0a11f1		 rtf-objdata-decoded RTF \objdata at offset 0x578C 1764 bytes

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