Malicious RTF — malware analysis report

Static analysis result for SHA-256 5e41401cc62f4ff5…

MALICIOUS

RTF

14.3 KB First seen: 2023-03-02
MD5: b13a74dca15cc4c5b3e73d60c4f100e3 SHA-1: a67404eb18267d09a5d54f2e7ea9e85097bdd3f5 SHA-256: 5e41401cc62f4ff58c658edce9d1823e2f6f84a646c9aa1c7fbac7f091ebc614
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1559.001 Component Object Model Hijacking T1059.001 PowerShell T1027 Obfuscated Files or Information

The RTF document contains heuristics indicating the exploitation of CVE-2017-11882 through an embedded OLE object, specifically identified as 'equation.3'. The presence of \objupdate further suggests that this OLE object is automatically activated upon opening the document. This technique is commonly used to deliver a secondary payload.

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_off00001fea.bin
b8af5392558ad76508531d933c30dcd1b689b057c9e43e53f3a22f1dfb38f427		 rtf-objdata-decoded RTF \objdata at offset 0x1FEA 1337 bytes

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