Malicious RTF — malware analysis report

Static analysis result for SHA-256 924cd3bd98de0cd3…

MALICIOUS

RTF

9.6 KB
MD5: 4f9a3ec99cb88fe8b6ad1b3f67b3ae25 SHA-1: c6aa116ea73434d91153c76349f73372b4eb614d SHA-256: 924cd3bd98de0cd3075d17af2abcb51033902de9fcc069c3043d2cf5f8a49cb9
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.001 PowerShell

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) to achieve code execution. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics strongly indicates this exploit. The `RTF_OBJUPDATE` heuristic suggests that the embedded OLE object is automatically activated upon opening the document, leading to the exploit's execution. No document body text or scripts were available for further analysis, but the exploit itself is sufficient to classify the attack pattern.

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_off0000101e.bin
dca317a6b17b194e440aa621328c053000f82f9f0df8ecc02f548e57a994a104		 rtf-objdata-decoded RTF \objdata at offset 0x101E 1718 bytes

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