Rtf.Downloader.CVE_2017_6336326-3 — RTF malware analysis

Static analysis result for SHA-256 1a62f3ca46a0b65d…

MALICIOUS

RTF

249.9 KB Created: 2017-12-18 11:56:00 First seen: 2017-12-24
MD5: 95a042a56c698f90b7225d1ccdc7973b SHA-1: 451287dc2c4ff8e736cf939640ba9e852f1ec482 SHA-256: 1a62f3ca46a0b65de73abe3792c02fe1af55c88950331271b2d6cf3eb5ff04da
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
    00013731  64a130000000      mov eax, dword ptr fs:[0x30]
00013737  90                nop
00013738  8b400c            mov eax, dword ptr [eax + 0xc]
0001373B  60                pushal
0001373C  61                popal
0001373D  8b4014            mov eax, dword ptr [eax + 0x14]
00013740  e9f7000000        jmp 0x1383c
00013745  0000              add byte ptr [eax], al
00013747  0000              add byte ptr [eax], al
00013749  0000              add byte ptr [eax], al
0001374B  0000              add byte ptr [eax], al
0001374D  0000              add byte ptr [eax], al
0001374F  0000              add byte ptr [eax], al
00013751  0000              add byte ptr [eax], al
00013753  0000              add byte ptr [eax], al
00013755  0000              add byte ptr [eax], al
00013757  0000              add byte ptr [eax], al
00013759  0000              add byte ptr [eax], al
0001375B  0000              add byte ptr [eax], al
0001375D  0000              add byte ptr [eax], al
0001375F  0000              add byte ptr [eax], al
00013761  0000              add byte ptr [eax], al
00013763  0000              add byte ptr [eax], al
00013765  0000              add byte ptr [eax], al
00013767  0000              add byte ptr [eax], al
00013769  0000              add byte ptr [eax], al
0001376B  0000              add byte ptr [eax], al
0001376D  0000              add byte ptr [eax], al
0001376F  0000              add byte ptr [eax], al
00013771  0000              add byte ptr [eax], al
00013773  0000              add byte ptr [eax], al
00013775  0000              add byte ptr [eax], al
00013777  0000              add byte ptr [eax], al
00013779  0000              add byte ptr [eax], al
0001377B  0000              add byte ptr [eax], al
0001377D  0000              add byte ptr [eax], al
0001377F  0000              add byte ptr [eax], al
00013781  0000              add byte ptr [eax], al
00013783  0000              add byte ptr [eax], al
00013785  0000              add byte ptr [eax], al
00013787  0000              add byte ptr [eax], al
00013789  0000              add byte ptr [eax], al
0001378B  0000              add byte ptr [eax], al
0001378D  0000              add byte ptr [eax], al
0001378F  0000              add byte ptr [eax], al
  • \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

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