Malicious RTF — malware analysis report

Static analysis result for SHA-256 546c12df39d3f2a8…

MALICIOUS

RTF

13.8 KB First seen: 2019-08-04
MD5: 6befbbff25eb423d0d8c5bb1eda3cfe4 SHA-1: acb7c1e580e5c4806e0522a863c0e735e9e1313b SHA-256: 546c12df39d3f2a853a3d5e98625b530a638528040118456ccf6317fd5c0d438
240 Risk Score

Malware Insights

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

The RTF file contains critical heuristics indicating the exploitation of CVE-2017-11882 via an embedded Equation Editor OLE object. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_EQUATION_OLE10NATIVE` strongly suggests this vulnerability is being leveraged. The `RTF_OBJUPDATE` heuristic indicates that the embedded object is designed to be activated, likely to execute a malicious payload. The document body content is heavily obfuscated and does not provide clear textual lures, but the technical indicators are definitive.

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.
  • \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_off000014cf.bin rtf-objdata-decoded RTF \objdata at offset 0x14CF 4155 bytes
SHA-256: 178a752aae00b48cf47040ab39559622aa866f099db2c77fa7f13c46e85babb1

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