Malicious RTF — malware analysis report

Static analysis result for SHA-256 0b67ea1815b1195c…

MALICIOUS

RTF

4.6 KB First seen: 2019-02-10
MD5: 6018f0ea0b3b41aebe9e6acfa2079d4e SHA-1: fb1026e5df15753f6838147371a5df21daa452b8 SHA-256: 0b67ea1815b1195c93d3617064159e1feaefb3835e61ce900947d1c2d2ac7dd7
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data and triggers heuristics indicating the use of the Equation Editor vulnerability (CVE-2017-11882). The ".objupdate" heuristic suggests that the embedded object is automatically activated upon opening, leading to the execution of the exploit. The presence of 'eqnedt.exe' in the decoded object data further supports this. This technique is commonly used to deliver secondary payloads via spearphishing attachments.

Heuristics 3

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003c.bin rtf-objdata-decoded RTF \objdata at offset 0x3C 2320 bytes
SHA-256: bb87ecd5e56a406d84cd1f9c4aea7a6f87c4a5763086b5258a5069a12fae8684

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