Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdb83ac8e0ad2e29…

MALICIOUS

PDF

87.2 KB Created: 2021-07-30 14:53:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 9f06073cfae8114f9763cae74bf9b4f3 SHA-1: d50690c9de2650aaba5885862439e8664d8ea26d SHA-256: cdb83ac8e0ad2e298d609a891b41443bc1ff58f53d69914eddd301d88e8094ef
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a high-confidence ML classification and a ClamAV detection for phishing and trojan activity. It contains numerous embedded URLs pointing to compromised CMS uploads and disposable hosting, suggesting it functions as a link farm to distribute malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://allytemp.ru/uplcv?utm_term=what%27s+wrong+if+my+dryer+doesn%27t+heat+up PDF link annotation
    • http://nowyhotelik.pl/userfiles/file/xisujizerefiwef.pdfIn PDF document text
    • https://detskeihriska.eu/ckfinder/userfiles/files/61613262250.pdfIn PDF document text
    • https://canadiancontractorservices.com/wp-content/plugins/super-forms/uploads/php/files/p5gd5jafnu3825ll4i9lr0h9o1/pepox.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/8e954e8af25bb9ff4b46f5e5a99bce0e/45877374879.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/eaf508aaef722dc8a69373bf854abe79/85073462737.pdfIn PDF document text
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/160d30a9e465b1---41903989975.pdfIn PDF document text
    • http://upservice.expert/admin/ckfinder/userfiles/files/lerujexu.pdfIn PDF document text
    • https://debcopharma.com/userfiles/file/putav.pdfIn PDF document text
    • https://alakharia.com/public_html/userfiles/file/demuninorevakaba.pdfIn PDF document text
    • http://www.zulfugar.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608fc565523a3---rufasuvivetipixozedupozax.pdfIn PDF document text
    • http://snookerfootball.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1608dd50e35763---26223676277.pdfIn PDF document text
    • https://rrvchefs.com/wp-content/plugins/super-forms/uploads/php/files/02ba4f1aedf8c0ea4a6dfb7628eab1fd/12499848096.pdfIn PDF document text
    • http://tvtamminhphat.com/uploads/userfiles/file/11508190273.pdfIn PDF document text
    • http://www.empresasdelimpeza.info/wp-content/plugins/formcraft/file-upload/server/content/files/16092d39f294a6---zegepexaf.pdfIn PDF document text
    • http://www.viksexteriors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a421cde9f2a---45932814389.pdfIn PDF document text
    • https://smsenerji.com/resimler/files/lozumakajadowevarij.pdfIn PDF document text
    • https://www.pal-kont.hu/wp-content/plugins/super-forms/uploads/php/files/12809aa84150e09f3cb19d485b28ce8b/65799849652.pdfIn PDF document text
    • https://mut-zur-veraenderung-hambuch.de/userfiles/file/15481869937.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b0ca7dc0e6c---foxinupalu.pdfIn PDF document text
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/19b99746a0debd681863ba3054be4293/73644686955.pdfIn PDF document text
    • http://maidichike.com/upload/files/lefevenetul.pdfIn PDF document text
    • http://sosnovgeo.ru/userfiles/file/69007642742.pdfIn PDF document text
    • http://colorfulmedia.de/fotki/fotki/file/21287991144.pdfIn PDF document text
    • https://ontime-taxi.kg/wp-content/plugins/super-forms/uploads/php/files/2275b6d9b1f9a2d45b5a62a2d7c33328/8065130358.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_off0000f00a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF00A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001081c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1081C 16944 bytes
SHA-256: 2567442c51f395eaac9cf328d5480dd9ee16c1391896ab0c5cb589a427c9c941
font_02_sfnt_off00013443.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13443 11224 bytes
SHA-256: fe261a946b4bc0257e2316276d3fb96d8d82228fdfc9f95a4d80c6b689b8a3b1