Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6aefe0bd42c68c1a…

MALICIOUS

RTF / .DOC

43.2 KB First seen: 2023-05-08
MD5: c640945237e71cf74b8131254b284ab5 SHA-1: ad3d20ac212d909de105ea598c182a0f887cddbf SHA-256: 6aefe0bd42c68c1a2a4294c7923939ce5f68f892a21f1606772561b6c7037ce6
140 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with an Equation Editor ProgID, triggered by an \objupdate command. This strongly suggests an attempt to exploit a known vulnerability, likely CVE-2017-11882, to execute arbitrary code when the user enables editing. The document body contains academic text, serving as a lure to disguise the malicious payload.

Heuristics 4

  • 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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00005743.bin
364424d01a2209d204e5b2e4169882486b2cb5ceef1ecd01ebeb2419a0417252
rtf-objdata-decoded RTF \objdata at offset 0x5743 1936 bytes