Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d7823a960d75c5bf…

MALICIOUS

RTF / .DOC

25.7 KB
MD5: bfdb6dce35007dec37fd7420fa18efbb SHA-1: acf16447fbdf8398c5ed344926752ced8c156783 SHA-256: d7823a960d75c5bf7096fa886ed73adb1c5ded681e42999831b17076f36b617d
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The file is an RTF document containing an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit is designed to execute arbitrary code upon opening the document, likely leading to the download and execution of a secondary payload. The specific exploit targeted is Equation Editor activation.

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 2 \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_off00001d58.bin
8e99f94939dd078a0d92e03d419cb798b4cc86c068b2745dca3334d734a490c4
rtf-objdata-decoded RTF \objdata at offset 0x1D58 1713 bytes