Malicious RTF — malware analysis report

Static analysis result for SHA-256 12c7f6b380299a45…

MALICIOUS

RTF

18.9 KB First seen: 2018-07-23
MD5: 33ef12145e3141d35a0a729fe3038163 SHA-1: d958d2aa3f952ec682bf5c42685e92b78c3cec96 SHA-256: 12c7f6b380299a45bae0d9c46baf0e160e4e65caa3179f3bb7df7d58e626e8f1
200 Risk Score

Malware Insights

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

The sample is an RTF document containing an OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This technique is commonly used to execute arbitrary code, likely to download and run a second-stage payload. The presence of the Ole10Native stream is a strong indicator of this exploit.

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_off000014c1.bin rtf-objdata-decoded RTF \objdata at offset 0x14C1 4668 bytes
SHA-256: 3bcfe382e4a19210ed1bcb9e98d97cd73e1b18f96ea3c4c905ee58064eac8564