Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 48c3e5f17f39d951…

MALICIOUS

RTF / .DOC

2.24 MB
MD5: 2263462d1ad97ed35943c3cd852bf324 SHA-1: aae47d347e5e806a1fe81068bf34596377c79434 SHA-256: 48c3e5f17f39d951fe3b1524c7ddcf030642bcb912b23526083995c15a172f36
180 Risk Score

Malware Insights

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

The file is an RTF document that contains an embedded OLE object, specifically identified as an Equation Editor object. Heuristics indicate the exploitation of CVE-2017-11882, a known vulnerability in Microsoft Equation Editor, which allows for arbitrary code execution. The embedded object is updated via \objupdate, forcing activation and triggering the exploit. The decoded object data contains what appears to be VBScript code, likely intended to download and execute a second-stage 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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001202.bin
477224e1cffa2168ce69598422c172e2c5bd57899b5654ebeb9d6267f654c1aa		 rtf-objdata-decoded RTF \objdata at offset 0x1202 27204 bytes
objdata_01_off0001ce95.bin
420dd98e97f2838b69fef2f6d85eff987f569ee4001ae1d6183f751f72b4b727		 rtf-objdata-decoded RTF \objdata at offset 0x1CE95 480330 bytes

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