Malicious RTF — malware analysis report

Static analysis result for SHA-256 70418469eb481292…

MALICIOUS

RTF

9.4 KB First seen: 2018-08-14
MD5: f3b43686bba25d5bc8c517863f7e3923 SHA-1: 91b75e287f79282a8c3cb27dc631269392c9cf4b SHA-256: 70418469eb481292b544e52dab696121f0492a110a99240d8194e5eb208a4ef1
320 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data, specifically targeting the Equation Editor with a known exploit for CVE-2017-11882. This exploit allows for the execution of arbitrary code, which is likely used to download and execute a secondary malicious payload. The presence of the Equation Editor CLSID and Ole10Native stream strongly indicates this exploit vector.

Heuristics 7

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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.
  • ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • 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_off00000978.bin rtf-objdata-decoded RTF \objdata at offset 0x978 3621 bytes
SHA-256: 0c99528d5ee0cd269144d6427dabaf05dc68f24472cd499c078e8617b5c53b25