Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 77cca44289df3154…

MALICIOUS

RTF / .DOC

402.2 KB Created: 2020-06-09 12:34:00 First seen: 2021-07-02
MD5: ced28e976c012f534d2fed694794aeee SHA-1: d1072afe6f35a65e5d275e7899fbfc321b0a14b8 SHA-256: 77cca44289df31547e885a458accdf04521254750ffd50d2815207c452ba2d6d
322 Risk Score

Malware Insights

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

The RTF document exploits vulnerabilities CVE-2017-0199 and CVE-2017-8759 using OLE2Link remote moniker loading, and CVE-2017-8570 via composite monikers. These exploits are designed to download and execute a second-stage payload, likely delivered via an embedded OLE object. The document body content appears to be garbled or irrelevant, providing no direct clues to the lure.

Heuristics 9

  • Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570
    RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
  • CVE-2017-0199 / CVE-2017-8759 (OLE2Link auto-activated remote loader) critical CVE related RTF_OLE2LINK_REMOTE_MONIKER_LOADER
    RTF embeds an OLE2Link object that is force-activated with \objupdate (no user interaction on open) and fetches a remote second stage — through an INCLUDETEXT/INCLUDEPICTURE field or the OLE object's own moniker. This is the OLE2Link auto-update attack path shared by CVE-2017-0199 (server returns an HTA/scriptlet) and CVE-2017-8759 (server returns a SOAP WSDL the .NET parser compiles). Office processes the fetched response through the same code path; the specific CVE depends on the now-unreachable server content type.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • 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.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • OLE object data medium RTF_OBJDATA
    RTF contains 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000132c1.bin rtf-objdata-decoded RTF \objdata at offset 0x132C1 56433 bytes
SHA-256: 5f667762fe1eeca0e2c1ce55a3c66d7d1a9177cfc6fba58a4358c47ee451d9f1
objdata_01_off00019a70.bin rtf-objdata-decoded RTF \objdata at offset 0x19A70 56406 bytes
SHA-256: 8590326df6a49cb353ce71093e7109e4cc75efc30997d88b34d468ba2ae62c63
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off0003655d.bin rtf-objdata-decoded RTF \objdata at offset 0x3655D 2632 bytes
SHA-256: a8e170497da15decc11753d202c99c86f7a7ffd2d52481e6b9c79a5403675379
objdata_03_off00037b00.bin rtf-objdata-decoded RTF \objdata at offset 0x37B00 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7