Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 9cfea93f84c6493d…

MALICIOUS

RTF / .DOC

5.1 KB First seen: 2022-06-17
MD5: afccc7f8523a2849c30b208454fff816 SHA-1: e5dc0b49acbcecb94c7cffc8626ed1f24eec5e75 SHA-256: 9cfea93f84c6493d327dcf54fc10d4e0b9f3dd68c3f5f5e4d87c038a89e987b3
120 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and triggers the Equation Editor exploit. The ".objupdate" directive forces the activation of this embedded object, which is a known method for exploiting the Equation Editor vulnerability (CVE-2017-11882). This technique is commonly used to deliver a second-stage payload.

Heuristics 3

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000a3.bin
cb4b31585750a3c9884d681d01db68d84dfb60fc791c6b1541b61461ff69d770
rtf-objdata-decoded RTF \objdata at offset 0xA3 2206 bytes