Malicious RTF — malware analysis report

Static analysis result for SHA-256 c46406e55502a49f…

MALICIOUS

RTF

260.5 KB First seen: 2019-05-10
MD5: 489afaa6c5e92b61f01405753911e44a SHA-1: 115bd01c310599f59377d5ead29602389abb633f SHA-256: c46406e55502a49f4fec4914be5fbac6833e96ac7deafa1f2f1cf4f36703708a
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit allows for the execution of arbitrary code, likely to download and run a secondary payload. The file's structure and the specific heuristic firings strongly indicate this exploitation method.

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_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 67606 bytes
SHA-256: 37d8b4508efbafccb129bb124c023f7bf9433505cdcc593670e4c6647203eed4