Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4e1c9dafeb733168…

MALICIOUS

RTF / .DOC

23.7 KB First seen: 2023-01-24
MD5: f84ce914a6c913fd32119823d456b5d2 SHA-1: 9d9c7ae03fb2ae3c1bd86077008e95a982a0471a SHA-256: 4e1c9dafeb733168680cfb000a4bf023e0851b1ee250dcf66677ff92cfa7387d
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell T1027 Obfuscated Files or Information

The RTF document contains an embedded OLE object specifically identified as related to CVE-2017-11882, leveraging the Equation Editor vulnerability. The presence of \objdata and \objupdate directives indicates an attempt to force OLE activation, which is a common method for exploiting this vulnerability to execute arbitrary code. The document also contains a lure instructing the user to 'Enable editing', further supporting its role as a malicious dropper.

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_off000048d0.bin
a995d1371031b9e6536e0aa265259440e4b77853f55fdab8fbfd29f4f9f475d2		 rtf-objdata-decoded RTF \objdata at offset 0x48D0 1610 bytes

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