Malicious RTF — malware analysis report

Static analysis result for SHA-256 1a056d1c3dc81bac…

MALICIOUS

RTF

9.3 KB First seen: 2020-02-04
MD5: 8218f30b85cfae1d15f5eb9401b01b14 SHA-1: 46a544bed4d22f501f63d45e6ecfac68dbe6452d SHA-256: 1a056d1c3dc81bac21e138175ef5dcb05b4c8930063db4fd5d24acb33723ac05
260 Risk Score

Malware Insights

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

The RTF file contains critical heuristics indicating the presence of a payload exploiting CVE-2017-11882 via Microsoft Equation Editor. This vulnerability allows for arbitrary code execution, likely to download and execute a second-stage payload. The presence of OLE object data and specific CLSIDs further confirms the exploitation attempt.

Heuristics 6

  • 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.
  • 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_off000004d7.bin rtf-objdata-decoded RTF \objdata at offset 0x4D7 4144 bytes
SHA-256: 562f26538331795cefcaad94641243e3604832993894e103f7e595bbf494cfe8

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