Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5f083eaacf56fd9…

MALICIOUS

PDF

83.0 KB Created: 2021-09-16 03:10:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 462ba5ac56ca5067de78a5127e5453ad SHA-1: d2d54bfd399a0376613ee15024af85af837eb5e3 SHA-256: a5f083eaacf56fd9332dbab4f86626c68e252ed2460dc1df4c0da62b27b1008f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to disposable domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://pacpartner.net/images_client/imagesfile/95399557830.pdf In PDF document text
    • http://optimumnieruchomosci.pl/uploads/userfiles/files/68362053159.pdfIn PDF document text
    • http://boilerservis.ru/uploads/files/fomesegegolulopalowi.pdfIn PDF document text
    • https://vietnam-pump.com/userfiles/file/moxukelok.pdfIn PDF document text
    • https://www.igescanada.com/ckfinder/userfiles/files/36126491477.pdfIn PDF document text
    • https://sailstudy.in/ckfinder/userfiles/files/13820380843.pdfIn PDF document text
    • http://ch-yang.com/upload/files/73948878150.pdfIn PDF document text
    • http://cariboohose.com/userfiles/file/90171982588.pdfIn PDF document text
    • http://yjeverspeed.com/userfiles/file/lozovuvupevakigi.pdfIn PDF document text
    • https://learnrkbin.jugalbandiresearch.com/ckfinder/userfiles/files/11883302801.pdfIn PDF document text
    • http://life-homeshop.com/asset/uploads/files/tozef.pdfIn PDF document text
    • http://humanitool.ru/userfiles/file/vufefovajivefekerom.pdfIn PDF document text
    • https://tonymusic.se/UserFiles/files/22812819400.pdfIn PDF document text
    • http://lapenya.cat/imgjovesnaves/file/sarubapilabera.pdfIn PDF document text
    • http://nsk-nalogov.net/upload/files/gefepo.pdfIn PDF document text
    • http://domusanna.it/userfiles/files/kipajobin.pdfIn PDF document text
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161408fc43aaba---29803923625.pdfIn PDF document text
    • http://kfnmdg.com/upfolder/e/files/20210911141434.pdfIn PDF document text
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/7mh7s7rdb4hleted9g8kjmm1mt/75708350522.pdfIn PDF document text
    • http://e-sportis.com/images/upload/jililisokowujefuzaposiwu.pdfIn PDF document text
    • http://liceoadultos.juniorcollege.cl/userfiles/files/1287906332.pdfIn PDF document text
    • http://dungcucaytrong.com/images/files/filirumegutelusuz.pdfIn PDF document text
    • http://fkhd.cz/data/img/bekisefijapomivulatifejed.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=describe+the+divisions+of+the+nervous+systemPDF 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_off0000e28b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE28B 16728 bytes
SHA-256: 19ada5e60e9a71fbb5467d719fa07b1c4fd0bde23bc8e31fcaa399debb79542f
font_01_sfnt_off00010cb4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CB4 10952 bytes
SHA-256: 183c2425ee066e8ee40acdc34d74fcd1476e483ff758fb1605c609081308eafa
font_02_sfnt_off00012600.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12600 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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