Malicious RTF — malware analysis report

Static analysis result for SHA-256 165ecf32dae08d23…

MALICIOUS

RTF

274.9 KB First seen: 2017-12-09
MD5: 70775f423c6cd332e5dc56292e13c663 SHA-1: cac7b49d82fc9cde77774605332a42536db3f324 SHA-256: 165ecf32dae08d23e24f7ad4ca8263b5992d2b67032531a559a0a64e8464229e
382 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059 Command and Scripting Interpreter

The RTF document contains OLE object data that leverages remote monikers, indicating exploitation of CVE-2017-0199 or CVE-2017-8759. The embedded URL http://37.233.101.29/t/t.php?stats=send&thread=0 is likely used to download and execute a secondary payload. References to CreateProcess, ShellExecute, LoadLibrary, and GetProcAddress APIs further support the execution of malicious code.

Heuristics 10

  • 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. This is the field-delivered 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.
  • ClamAV: Rtf.Downloader.CVE_2017-6336326-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Downloader.CVE_2017-6336326-3
  • Reference to CreateProcess API high SC_STR_CREATEPROCESS
    Reference to CreateProcess API
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • \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.
  • INCLUDETEXT/INCLUDEPICTURE remote URL high RTF_INCLUDE_REMOTE
    RTF document uses INCLUDETEXT or INCLUDEPICTURE with an http:// URL — Word can fetch the remote content on open depending on Office version and external-content settings, enabling remote template injection, NTLM capture via redirects, or payload delivery
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • 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://37.233.101.29/t/t.php?stats=send&thread=0 In RTF body
    • http://nsis.sf.net/NSIS_ErrorIn RTF body

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000c290.bin rtf-objdata-decoded RTF \objdata at offset 0xC290 2598 bytes
SHA-256: 17b2ca9b90c3d3447b8da4ef00335f110cd8cf08ffee760ba4c74ff30ca35d2a
objdata_01_off0000d9be.bin rtf-objdata-decoded RTF \objdata at offset 0xD9BE 2674 bytes
SHA-256: d884dbd54359cd7acfb06b611bacf6d6a5994b8519007c873d91a5b688fdd8c1

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