Malicious PDF — malware analysis report

Static analysis result for SHA-256 2891b3f4e5dfa7f2…

MALICIOUS

PDF

79.8 KB Created: 2021-09-17 07:23:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 171aa33f12ca930a1b86822a7c6e33a4 SHA-1: 165a471ac11e2c5d2a0b24108f30f59fea0fa5c6 SHA-256: 2891b3f4e5dfa7f286d2e9fddbede69fc0f40fabd4ee7d54b5dcf0c18dab020e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many of which are hosted on disposable domains or appear to be compromised WordPress uploads, suggesting a link farm or phishing lure. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' reinforces this. The primary attack pattern involves directing users to these external sites, likely for further exploitation or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://nomylo.ru/uplcv?utm_term=internal+memory+full+android+problem PDF link annotation
    • http://koyomisushi.com/uploads/files/gabikazaziwe.pdfIn PDF document text
    • http://kolaykanal.com/userfiles/files/15769152116.pdfIn PDF document text
    • http://vicc.huh.hu/UserFiles/File/sidoxonegedesizekap.pdfIn PDF document text
    • http://ph-easycome.com/userfiles/file/50816294777.pdfIn PDF document text
    • https://kanalprofi.at/UserFiles/file/47400398429.pdfIn PDF document text
    • http://businessvaluationapp.com/fck_files/file/darudi.pdfIn PDF document text
    • https://lawyerupsmart.com/tempimg/file/5037891875.pdfIn PDF document text
    • http://boras-sjuharad.boj.se/uploads/userfiles/files/daditalebo.pdfIn PDF document text
    • http://tdbakademi.org/userfiles/files/75017735273.pdfIn PDF document text
    • https://apteka-wratislavia.pl/halatecza/userfiles/file/paguzumupaw.pdfIn PDF document text
    • http://dalhousieretreat.com/cote_dor_import/admin/ckfinder/userfiles/files/bopizadujokiduta.pdfIn PDF document text
    • https://pharma-tools.eu/galeria/file/5257185619.pdfIn PDF document text
    • http://alnadaoil.com/userfiles/file/88384642840.pdfIn PDF document text
    • http://kondicionery-elektrostal.ru/upload_picture/file/mulabetij.pdfIn PDF document text
    • http://anhuicrew.com/upload_fck/file/2021-9-11/20210911212748911485.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613188b8ed673---jozutuxoxibadizuboru.pdfIn PDF document text
    • http://phayaotechno.com/UserFiles/File/xoxaruxodiji.pdfIn PDF document text
    • https://digitaluzaktanegitim.com/calisma2/files/uploads/kijijawezineramusomuzaz.pdfIn PDF document text
    • https://iskoruma.com/upload/ckfinder/files/lugerewesebam.pdfIn PDF document text
    • https://sakitonus.ru/wp-content/plugins/super-forms/uploads/php/files/c36acbbc33d19ea4a9c8f19c5d8b31d3/35262147559.pdfIn PDF document text
    • https://dacola.com/upload/files/22883527943.pdfIn PDF document text
    • http://photopuzzle.net/userData/board/file/19280136059.pdfIn PDF document text
    • https://marblobaths.ph/app/webroot/img/files/xanuwupidalunejamazoluvuz.pdfIn PDF document text
    • http://cuacuonanbinh.com/userfiles/file/85768128145.pdfIn PDF document text
    • https://membermimpi.com/contents/files/22059809261.pdfIn PDF document text
    • http://www.coverseg.com/uploads/ckfinder/files/tufivusoviwegapelikofani.pdfIn PDF document text
    • https://dezsredstvompx.ru/wp-content/plugins/super-forms/uploads/php/files/3b3214eb5265742f96f55e1f9cdc895d/78644621944.pdfIn PDF document text
    • 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_off0000d3e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3E5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ebf7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBF7 17480 bytes
SHA-256: d17a7e2354a49632176260172f5c3a73e84792f61f1da4928ce35634c81499d2
font_02_sfnt_off000118a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118A7 10796 bytes
SHA-256: ba73715de5a31e2fc535acd7fa0d05ac1c5ff588ab5854d5a48209b57d3e89b4

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