Malicious RTF — malware analysis report

Static analysis result for SHA-256 f3451004f223ecaf…

MALICIOUS

RTF

14.2 KB First seen: 2018-11-05
MD5: b8a196c40522552d9454e4919b23be72 SHA-1: e4ad90c8d6e4051b23e5d1223ee0414cf85f9b11 SHA-256: f3451004f223ecafc7f07a0c57b5d73a010ab2ff516ed792eb30ed9fc952b8f6
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit is designed to execute arbitrary code, likely to download and run a second-stage payload. The presence of the OLE object and the specific heuristic firings strongly indicate exploitation of this known vulnerability for client execution.

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.
  • \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_off000007ff.bin rtf-objdata-decoded RTF \objdata at offset 0x7FF 4155 bytes
SHA-256: 6382121980bf2635c42436f6c861a2d23b4e573cfe38372a5616bb09186c60c7