Malicious RTF — malware analysis report

Static analysis result for SHA-256 38b1fc72e2d64f72…

MALICIOUS

RTF

14.3 KB First seen: 2019-01-20
MD5: 9425e99e9c32db61cc5d8c0c64b29afa SHA-1: 5de913735d740f1e1fcf218bbb1da96e833b22d6 SHA-256: 38b1fc72e2d64f72e6283379545f4e8a2c03116f000729b2daecb4f495faf1ed
220 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This is a critical finding, indicating the file is designed to exploit this specific flaw for client-side execution. The presence of the OLE object and the ".objupdate" directive strongly suggest an attempt to trigger the exploit upon opening. Given the nature of this exploit, it is highly probable that it serves as a dropper for a secondary malicious payload.

Heuristics 5

  • 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
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000014bd.bin rtf-objdata-decoded RTF \objdata at offset 0x14BD 4644 bytes
SHA-256: 5362dc5923a7e31992a6c53878c94bc783acaa44bbe3b27b1c01e3b7cd0b8e7c