Malicious PDF — malware analysis report

Static analysis result for SHA-256 8dc73d8ff0ea138c…

MALICIOUS

PDF

83.3 KB Created: 2021-09-18 15:47:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 3818af3e55fe27df32a400995d816cf6 SHA-1: 20caeb290b7187da1512645d8fae6dbc8a57adc3 SHA-256: 8dc73d8ff0ea138caf8ace6c81607272d633c238f89c40b1e22d169f779043c3
164 Risk Score

Malware Insights

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

The sample was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to compromised WordPress uploads and other potentially malicious sites. The presence of a 'download button' lure further supports a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://urology-andrology.com/userfiles/file/jomite.pdf In PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/161409a0a7244b---210308276.pdfIn PDF document text
    • https://rafaela-motores.com/userfiles/file/14063527186.pdfIn PDF document text
    • http://wmc21.com/ckupload/files/26938579607.pdfIn PDF document text
    • http://www.mediacomriccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613d86be45adf---79489280253.pdfIn PDF document text
    • http://donghozibistore.com/luutru/files/32747045983.pdfIn PDF document text
    • https://elitestrategyglobal.com/wp-content/plugins/super-forms/uploads/php/files/6db2a1c119a7efd82598530e6d7854e5/kebazajofejir.pdfIn PDF document text
    • https://vcubusinesssolutions.com/userfiles/file/48291701309.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/29f265125850db85a935d06814287efb/zelatabid.pdfIn PDF document text
    • https://agmatbaa.com/upload/files/66418879931.pdfIn PDF document text
    • http://holland-ex.com/images/blog/file/vemategap.pdfIn PDF document text
    • http://arunimaflavours.com/userfiles/file/29527534528.pdfIn PDF document text
    • http://zabbeleecooking.com/ckfinder/userfiles/files/towajukipe.pdfIn PDF document text
    • http://allivecoat.com/userData/board/file/mubofatuzagadanezomanuvaj.pdfIn PDF document text
    • https://cornwallstaffagency.com/userfiles/file/pituwujupisipagenanud.pdfIn PDF document text
    • https://pointvirgule.ca/upload/editor/file/8680961369.pdfIn PDF document text
    • http://7166867.ru/ckfinder/userfiles/files/69542391103.pdfIn PDF document text
    • https://pierrelemagicien.com/userfiles/file/jonidelixubitos.pdfIn PDF document text
    • http://123podkrovie.sk/editor_uploads/files/75136555596.pdfIn PDF document text
    • https://www.agencesramos.com/ckfinder/userfiles/files/29180343662.pdfIn PDF document text
    • http://bfr-bialapodlaska.pl/userfiles/file/13996214040.pdfIn PDF document text
    • https://maidintown.co.uk/wp-content/plugins/super-forms/uploads/php/files/434b7350aa6a3ba14ddcc3e1332acb54/42408868670.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=convert+android+to+flutterPDF 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_off0000dca3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCA3 19332 bytes
SHA-256: f0481df989904f9f658b2bea1fa83083246ea4dff16076a6c183d4364b890d1e
font_01_sfnt_off00010feb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10FEB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012802.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12802 10376 bytes
SHA-256: b0b37eb44c61f6f29f0b813eb783b3a27aac635168517d9be8fc28d15da82674