Malicious RTF — malware analysis report

Static analysis result for SHA-256 8e107b7cc6913c49…

MALICIOUS

RTF

10.0 KB
MD5: 50d4dddb1000e7e62508148c84aa5f59 SHA-1: 923bf79912f95526b2dab00accf3de4ec3ab2f9c SHA-256: 8e107b7cc6913c49b057fce4573694813028ed01cf47fa54b277c1ce50ac4216
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for arbitrary code execution when the malformed OLE object is activated. The heuristics indicate the presence of an embedded OLE object and specific indicators related to the Equation Editor exploit. The document body is heavily obfuscated and does not provide clear textual lures, but the exploit itself is the primary attack vector.

Heuristics 5

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000145d.bin
9d4b59065ac48b60dee4cd1f08a3f6e96e5dae9d4491289cf5e705e7b7fb6a6b		 rtf-objdata-decoded RTF \objdata at offset 0x145D 1507 bytes

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