Malicious RTF — malware analysis report

Static analysis result for SHA-256 1b1b0c0606a8173f…

MALICIOUS

RTF

18.7 KB First seen: 2019-03-10
MD5: 1a5152fd1ddf2a06334a978a4c5c64a1 SHA-1: dd4bd655b0e5fee1884a690951fc301b0e487dac SHA-256: 1b1b0c0606a8173fb73c9d194d14797120a229fbad95d1beae3affe66508e6c5
200 Risk Score

Malware Insights

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

The RTF file contains an OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit is commonly used to execute arbitrary code, typically to download and run a second-stage payload. The presence of the Ole10Native stream and the objupdate heuristic further confirm the exploitation of this vulnerability for code execution.

Heuristics 5

  • Equation Editor Ole10Native payload — CVE-2017-11882 likely critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    RTF decodes to an activated Microsoft Equation 3.0 OLE storage whose payload is a high-entropy Ole10Native stream rather than normal Equation Native/MTEF data. This is a weaponized Equation Editor RCE delivery shape consistent with CVE-2017-11882/CVE-2018-0802.
  • Ole10Native stream in RTF OLE object high CVE related RTF_OLE10NATIVE_STREAM
    RTF contains an embedded OLE object with an Ole10Native stream. This is a strong payload-container signal and is related to Word/OLE exploit delivery, but it is not specific enough on its own to assign a CVE.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00001a75.bin rtf-objdata-decoded RTF \objdata at offset 0x1A75 4131 bytes
SHA-256: 10ac95e34dbe7c5173707d0acf3d3cdd236ef4b90058330938f75e96d65fe7d3

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