Malicious RTF — malware analysis report

Static analysis result for SHA-256 788b1e2a097cb1d0…

MALICIOUS

RTF

52.3 KB First seen: 2017-12-24
MD5: 257b52980f3561dd716f4df10228696e SHA-1: 407390686bd3a3350b7072bd7a1682ae1b859d79 SHA-256: 788b1e2a097cb1d033bc7104507870cd8d14daab0ee601e01c2ad62cd2e6cc62
160 Risk Score

Malware Insights

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

The RTF file contains OLE object data that is automatically linked and updated, triggering exploitation of CVE-2017-0199 or CVE-2017-8759. This vulnerability allows for the remote loading and execution of a second-stage payload embedded within the OLE moniker stream. The specific nature of the second-stage payload could not be determined statically.

Heuristics 4

  • 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.
  • 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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003f.bin rtf-objdata-decoded RTF \objdata at offset 0x3F 3132 bytes
SHA-256: e21e1073f4092716c4c9899c91e50a3588419030b34d9a63c410f837ddf0c65c