Malicious PDF — malware analysis report

Static analysis result for SHA-256 44090122421ed9ec…

MALICIOUS

PDF

88.9 KB Created: 2011-09-20 10:38:42 +08:00 Authoring application: WPS Office 个人版 (via PDFlib 7.0.3 (C++/Win32))
MD5: e30d11eb28bb88681d1fb31da88d84c6 SHA-1: c6c35a351c2511021c2490c99799824b14fa33e2 SHA-256: 44090122421ed9ec15212e0336a49df03b98f61675f097eb54f426baecfd084a
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious Link

The PDF exhibits characteristics of a phishing lure, including being image-heavy with a click-outward action. Heuristics indicate the presence of embedded files, JavaScript, and RichMedia (Flash), suggesting an attempt to deliver a malicious payload. The ML classifier strongly flagged this PDF as malicious. The presence of embedded files, though their content is not detailed, points towards a multi-stage attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 9

  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector (matched inside decoded stream)
  • Image-only document with action trigger (screenshot lure) medium PDF_IMAGE_LURE
    PDF has 2 image(s), only 1 text block(s), carries a click-outward action, and is only 88 KB — typical shape of a phishing lure where a full-page screenshot hides a clickable button that launches or submits to an attacker URL.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules. (matched inside decoded stream)
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules. (matched inside decoded stream)
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic (matched inside decoded stream)
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 13

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0001.bin
3000b3469a8bd553f177da3f507a5ea2271a3dee1fd5d5343f41950837af583c		 pdf-embedded-file PDF EmbeddedFile object 1 at offset 0x3B36 163 bytes
embedded_file_obj0002.bin
66b82b096ae83103365f40b9b767a5582b0a497e4589e7b9323eac0320c61808		 pdf-embedded-file PDF EmbeddedFile object 2 at offset 0x3C27 1670 bytes
embedded_file_obj0003.bin
e763ac63c3d21786709e7f462b463575525d0e344202f42dbb96897a01541e78		 pdf-embedded-file PDF EmbeddedFile object 3 at offset 0x3F43 785 bytes
embedded_file_obj0004.bin
720c47f19e6a058099295d18a16b7149cc73fe497eb78821ea810f3192228dc4		 pdf-embedded-file PDF EmbeddedFile object 4 at offset 0x4138 150 bytes
embedded_file_obj0005.bin
c8a82f67dfd8d68c2f8fe494ca2deee4604701c8f02863bf87d222b992e45de9		 pdf-embedded-file PDF EmbeddedFile object 5 at offset 0x4209 2955 bytes
embedded_file_obj0006.bin
4cb349134bdb5f1a1c03281df9b53128ebe947f235398a912a4f0a9f638b24d5		 pdf-embedded-file PDF EmbeddedFile object 6 at offset 0x4583 200 bytes
embedded_file_obj0007.bin
4273cd319df227c91b92e5509527bb4f6e1abfb3aa2beec2fb2adb93a8671f62		 pdf-embedded-file PDF EmbeddedFile object 7 at offset 0x4676 835 bytes
embedded_file_obj0008.bin
4a60a9864cdf7382475d51051a03fdc43b32c31eb508893ccfccece34957f9f1		 pdf-embedded-file PDF EmbeddedFile object 8 at offset 0x484D 56 bytes
stream_002_off000003ed.js
529357503ec67b623d2a12816cdeea62bd639f2b4ff4e568b01c96cc3f5bfc6f		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x3ED 1363 bytes
stream_003_off000005ca.js
e985b5df65c8c3cf732a9074b575fbc594c1c7f0bccc0994182ec7e5c0f7308a		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5CA 902 bytes
objstm_0047_00.bin
856830b101f28eaa61f2ccb44204fecaa2d0a9658055009fda363a9d3056ff76		 pdf-objstm-decoded PDF /ObjStm 47 0 obj (inflated) 2543 bytes
polyglot_child_pdf_off0000f487.pdf
d9c10e812f4298ac0094217307ce52aedbf0c9ddf4efcd4c6cc14b04b8af0f83		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0xF487 28411 bytes
polyglot_child_pdf_off00014b93.pdf
9a95102ad6b4d58a9a742832f61490a27e9b62855fe295b13214addfda321ad3		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x14B93 6127 bytes

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