Rtf.Downloader.CVE_2017_6336326-3 — RTF malware analysis

Static analysis result for SHA-256 89103b1686520aac…

MALICIOUS

RTF

245.9 KB Created: 2017-12-18 11:56:00 First seen: 2017-12-24
MD5: 0bd002da124cbba23545b7a7597d1461 SHA-1: 427f6580993d3ac0cc092afaa5ca5af7fdf58b18 SHA-256: 89103b1686520aac734e3643d1bfc11fa785478e0a28333df4b409ae90bdf335
262 Risk Score

Malware Insights

Rtf.Downloader.CVE_2017_6336326-3 · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains OLE objects and uses \objupdate to force OLE activation, specifically exploiting CVE-2017-8759. It also includes a remote URL, http://todpot.tk/0346/t.php?stats=send&thread=0, which is likely used to download a secondary payload. ClamAV detection confirms this as a downloader.

Heuristics 7

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • ClamAV: Rtf.Downloader.CVE_2017-6336326-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Downloader.CVE_2017-6336326-3
  • PEB access via FS segment (x86) high SC_PEB_ACCESS
    PEB access via FS segment (x86)
    Disassembly
    Attempted x86 opcode disassembly
    0001392D  64a130000000      mov eax, dword ptr fs:[0x30]
    00013933  e9f7000000        jmp 0x13a2f
    00013938  0000              add byte ptr [eax], al
    0001393A  0000              add byte ptr [eax], al
    0001393C  0000              add byte ptr [eax], al
    0001393E  0000              add byte ptr [eax], al
    00013940  0000              add byte ptr [eax], al
    00013942  0000              add byte ptr [eax], al
    00013944  0000              add byte ptr [eax], al
    00013946  0000              add byte ptr [eax], al
    00013948  0000              add byte ptr [eax], al
    0001394A  0000              add byte ptr [eax], al
    0001394C  0000              add byte ptr [eax], al
    0001394E  0000              add byte ptr [eax], al
    00013950  0000              add byte ptr [eax], al
    00013952  0000              add byte ptr [eax], al
    00013954  0000              add byte ptr [eax], al
    00013956  0000              add byte ptr [eax], al
    00013958  0000              add byte ptr [eax], al
    0001395A  0000              add byte ptr [eax], al
    0001395C  0000              add byte ptr [eax], al
    0001395E  0000              add byte ptr [eax], al
    00013960  0000              add byte ptr [eax], al
    00013962  0000              add byte ptr [eax], al
    00013964  0000              add byte ptr [eax], al
    00013966  0000              add byte ptr [eax], al
    00013968  0000              add byte ptr [eax], al
    0001396A  0000              add byte ptr [eax], al
    0001396C  0000              add byte ptr [eax], al
    0001396E  0000              add byte ptr [eax], al
    00013970  0000              add byte ptr [eax], al
    00013972  0000              add byte ptr [eax], al
    00013974  0000              add byte ptr [eax], al
    00013976  0000              add byte ptr [eax], al
    00013978  0000              add byte ptr [eax], al
    0001397A  0000              add byte ptr [eax], al
    0001397C  0000              add byte ptr [eax], al
    0001397E  0000              add byte ptr [eax], al
    00013980  0000              add byte ptr [eax], al
    00013982  0000              add byte ptr [eax], al
    00013984  0000              add byte ptr [eax], al
    00013986  0000              add byte ptr [eax], al
    00013988  0000              add byte ptr [eax], al
    0001398A  0000              add byte ptr [eax], al
    0001398C  00                .byte 0x00
  • \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://todpot.tk/0346/t.php?stats=send&thread=0 In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000c568.bin rtf-objdata-decoded RTF \objdata at offset 0xC568 2598 bytes
SHA-256: 958c6a347deec34fdbed67e065f04e9c575f0e13a93ace15782bd6899a1c92b4
objdata_01_off0000dc96.bin rtf-objdata-decoded RTF \objdata at offset 0xDC96 2723 bytes
SHA-256: 0434dece3b60573ec8eb06a6a1d5a15200f352756c38de5d8672232bb14b3ada