Malicious RTF — malware analysis report

Static analysis result for SHA-256 53253f87274573b2…

MALICIOUS

RTF

8.1 KB First seen: 2018-11-20
MD5: 9cde2bb933414e0c232cfe44b6c64811 SHA-1: fafba3fab920e6b556187d55532619fdc4230b10 SHA-256: 53253f87274573b24ea46c6dc3e61f53ff5ee4e2788530ff96a3248c0714cf9c
300 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code when the OLE object is activated, likely leading to the download and execution of a secondary payload. The presence of the Ole10Native stream and the specific CLSID associated with Equation Editor strongly indicate this exploit.

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
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4139 bytes
SHA-256: 61694cfac615e2c9aa696b78f357658203ddfbe9f5896fa760e6e08358c21e05