Malicious PDF — malware analysis report

Static analysis result for SHA-256 853f1cfab5718ae4…

MALICIOUS

PDF

69.6 KB Created: 2021-05-27 02:08:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 68c36a40e9ca3ee13839d2dc4ac6df45 SHA-1: ae0a5ff813b12fb1976076678fb005995b7f1425 SHA-256: 853f1cfab5718ae4612d1e1d3bacc7ac064b7a127738c0788fa760e038824a38
164 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it is a link farm pointing to compromised WordPress uploads and disposable hosting. The document body, though heavily obfuscated, contains text related to 'accounts payable clerk' and 'wkhtmltopdf', suggesting a lure to disguise malicious links. The embedded URLs likely lead to further stages of the attack, such as phishing pages or malware downloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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 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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://queure.ru/uplcv?utm_term=how+to+be+an+accounts+payable+clerk PDF link annotation
    • http://sixtyguildersresearch.com/admin/photos/file/toveju.pdfIn PDF document text
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/da4ee9084a54c3dd432a9120875fd6e4/35174233491.pdfIn PDF document text
    • http://opalbiosciences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f381200c87---27681132041.pdfIn PDF document text
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16072dac6b135e---57542667897.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d4a1527abb---wipiponix.pdfIn PDF document text
    • https://ceadersvalet.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076fa33d991d---pejomimano.pdfIn PDF document text
    • http://poorclarescork.ie/images/64612019847.pdfIn PDF document text
    • https://rocksoliddesigns.biz/userfiles/file/naxesobixe.pdfIn PDF document text
    • https://www.ideaklinikbakirkoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607aabca63775---59443883881.pdfIn PDF document text
    • https://brokenspoke.com/wp-content/plugins/super-forms/uploads/php/files/907d62488e993082fbc881825a0bbbe6/43982604800.pdfIn PDF document text
    • https://earthideasawnings.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aca4263e3f1---fexidudejuvuwopefi.pdfIn PDF document text
    • http://www.barankayalar.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160a283c309054---9809450283.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/bhg9e9p6drvfvf849mhb4u5rg2/11594972081.pdfIn PDF document text
    • https://ladychief.com/wp-content/plugins/super-forms/uploads/php/files/ae2bb6a51390d54d024ebad34dac8417/48285092744.pdfIn PDF document text
    • https://aquariumfargo.com/wp-content/plugins/super-forms/uploads/php/files/4480af41341069114664b9860aa4f182/44386614982.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b63552727c---21299312761.pdfIn PDF document text
    • https://otdelkamos.ru/wp-content/plugins/super-forms/uploads/php/files/4f19c8470e5d9594cfeb990fdad3b465/gemujimifej.pdfIn PDF document text
    • http://www.annaleehuber.com/content_files/file/doxasedon.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d34e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD34E 5288 bytes
SHA-256: e4cb95d77292f474c2810ee6fb613cefeab48a2594b43524a6e6b394ccde1c71
font_01_sfnt_off0000e568.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE568 10616 bytes
SHA-256: a9d4155ce22018019c0ec8e2d25cbf023900773d2406d670aa3155eadbcf5339

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