Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 153d0278268d1ba4…

MALICIOUS

RTF / .DOC

295.5 KB First seen: 2021-05-04
MD5: dbecba4a6211aba561e0d36f9db4b1d2 SHA-1: f808acedb937fcf07cd2b2c801a84cf290272b65 SHA-256: 153d0278268d1ba4248fcc47b93d6098c023c22ae0148e570e5f97810ae1dc4a
340 Risk Score

Malware Insights

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

The RTF document contains multiple indicators of exploitation, specifically related to CVE-2017-8570 and CVE-2017-0199/CVE-2017-8759, which are known to drop SCT scripts or load remote content. The document body explicitly instructs the user to 'click Enable Editing', a common lure to bypass macro security. The embedded OLE objects and objdata sections strongly suggest the file is designed to exploit these vulnerabilities to download and execute a second-stage payload.

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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
🗂 Part of campaign: shared payload 3cd3b7d42e 51 samples

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000096e.bin rtf-objdata-decoded RTF \objdata at offset 0x96E 40504 bytes
SHA-256: a88c63606d0e180166543c8f36289268e36715af8d089019bd882d8dc6e77fb9
objdata_01_off0000711d.bin rtf-objdata-decoded RTF \objdata at offset 0x711D 40477 bytes
SHA-256: 65e8ecd1c35e716331245871f682d11cfb2509f5badf99f36d5cd7b3ace7f6f4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off0001ba9e.bin rtf-objdata-decoded RTF \objdata at offset 0x1BA9E 2632 bytes
SHA-256: 3cd3b7d42e5855c90d6d11c54ef2670ed8970441480cc23f7d39ef08fa1c935b
objdata_03_off0001d041.bin rtf-objdata-decoded RTF \objdata at offset 0x1D041 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7