Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 cd63eb1a31e10d44…

MALICIOUS

RTF / .DOC

149.9 KB First seen: 2024-05-28
MD5: 9b8874549759e715edf254f395617e84 SHA-1: 1f5efa3b2ee547ff9db075a2b239b54b363cf194 SHA-256: cd63eb1a31e10d44ddf34b2eace72a0f5f0443b863163f6cddd442380388bab9
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.005 Visual Basic

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document also contains a lure instructing the user to 'enable editing', which is a common tactic to bypass security measures. The presence of ".objdata" and ".objupdate" sections strongly suggests an attempt to exploit the Equation Editor to execute arbitrary code, likely for downloading and running a second-stage 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_off00009a1f.bin
7b50e7679a85143fd3bc6ba86d2a226b2f53424ce337387ed21ffcc223d5b7b7
rtf-objdata-decoded RTF \objdata at offset 0x9A1F 1731 bytes