Malicious PDF — malware analysis report

Static analysis result for SHA-256 8cef3accc9e1f0da…

MALICIOUS

PDF

81.6 KB Created: 2021-09-13 13:15:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 685d063db102609644542f149a929369 SHA-1: f73e021c421729b340bb04a5940824e874538e98 SHA-256: 8cef3accc9e1f0da26e5b346c0fd28ce7a8a5ac4cfdb4c8f5e18ca2be9090af2
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous links to external PDFs hosted on various domains, many of which appear to be disposable or low-reputation. The 'PDF_RANDOM_URL_LINK' and 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristics indicate a pattern of distributing malicious content through a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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://gowowdeli.com/uploads/files/ramowujogibudefijinusi.pdf In PDF document text
    • http://kiemdinhcan.com/Images_upload/files/88702074812.pdfIn PDF document text
    • http://indecomavo.pl/userimg/inc/59441503488.pdfIn PDF document text
    • http://dpsszczytno.pl/photo/file/41418046547.pdfIn PDF document text
    • http://efcosmetic.com/uploadfile/files/zakedoxajazisipudiratubat.pdfIn PDF document text
    • https://floridainvestment.cz/files/file/nuvave.pdfIn PDF document text
    • http://www.focitabor.hu/userfiles/file/20443660044.pdfIn PDF document text
    • https://vallejardin.com/wp-content/plugins/super-forms/uploads/php/files/4045040e3e38599480aaca73cec794f9/jogutotavazur.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/3497157987.pdfIn PDF document text
    • http://patronusalapitvany.hu/public_html/upload/kebojetimunelaxezo.pdfIn PDF document text
    • http://dermalab.pl/userfiles/file/wikanigofitewitibuz.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139a9d44aa73---kudigitiwis.pdfIn PDF document text
    • http://cn-daomeng.com/upload/userfiles/files/5cd51f9c777ad2e38aee5bffdb82d53c.pdfIn PDF document text
    • http://pzhjintai.com/upload/files/73650566735.pdfIn PDF document text
    • http://gaineyranchaz.com/userimages/97705930971.pdfIn PDF document text
    • https://observatoire-omic.org/documents/file/2170848468.pdfIn PDF document text
    • http://zhfangyuan.com/uploadfiles/files/bonixaluwamonudu.pdfIn PDF document text
    • http://lucidareemantenerepavimentifaidate.it/userfiles/files/zufisel.pdfIn PDF document text
    • http://sergeybazarov.ru/file/67358018710.pdfIn PDF document text
    • http://chia4kids.ru/ckfinder/userfiles/files/7867888429.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=room+database+android+interview+questionsPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d91a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD91A 10948 bytes
SHA-256: af76099ba2f43d837cd5aca37cbd5622870750bc5ecb130db76f7336d23ea610
font_01_sfnt_off0000f25c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF25C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010a6e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A6E 18116 bytes
SHA-256: b794d1021d87d8edf055d6e4915f33a1fc6691c6bda36d3b273836eb551d7e9f

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