Malicious PDF — malware analysis report

Static analysis result for SHA-256 b31a4ccb17a88e7c…

MALICIOUS

PDF

95.1 KB Created: 2021-06-26 13:54:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: f3e01f4c97a3a25ea9d301e1ab8f59a8 SHA-1: d233e9f8c474de4962fb74a5c1412442b4de00e7 SHA-256: b31a4ccb17a88e7c64292b09aeb1ec568701bb5c2d000f7d5023719d2cd30ff2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, with numerous embedded URLs pointing to compromised CMS upload directories and disposable hosting. These links likely serve as redirects for phishing or malware delivery, aligning with the Spearphishing Attachment technique.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • 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.
  • 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://chcial.ru/uplcv?utm_term=gizmo+answer+key+heat+transfer+by+conduction PDF link annotation
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/e7al3mjvpmhjai7k1d1hkonigf/midalukurodapa.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160c5ec9c6cc34---bapavimaredim.pdfIn PDF document text
    • http://sad-azov.ru/wp-content/plugins/super-forms/uploads/php/files/d48054a70b3c1685187ac3e40678cb3e/varoxadoj.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/hk6a8e1kp1nm9vlfgeuu38471g/gagegurebemab.pdfIn PDF document text
    • http://sorokolaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/50895764239.pdfIn PDF document text
    • https://adbetelparaguay.com/wp-content/plugins/super-forms/uploads/php/files/ec289deec930a536beef0fa3489e36cc/datomafewetel.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fe0d8d9766---tamalo.pdfIn PDF document text
    • https://hopefor.today/wp-content/plugins/super-forms/uploads/php/files/d0cfee8180f7275ab01558b63cf5b2d6/70800718664.pdfIn PDF document text
    • http://ofipapel.org//ckfinder/userfiles/files/61281248674.pdfIn PDF document text
    • http://vietxetai.com/wp-content/plugins/super-forms/uploads/php/files/el575jc3d6370iidh3s2ak5l9s/rujotelisewumo.pdfIn PDF document text
    • http://trainternational.in/wp-content/plugins/formcraft/file-upload/server/content/files/16092c454a1b2f---zovixoxi.pdfIn PDF document text
    • http://www.segurosfacility.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ce7ae8453d3---3931612491.pdfIn PDF document text
    • https://www.asahinafunnels.com/wp-content/plugins/super-forms/uploads/php/files/o7maqpa8bpjs4t9gs85sg7b766/mozawedodube.pdfIn PDF document text
    • http://novelinternationalschool.com/ckfinder/userfiles/files/45682767007.pdfIn PDF document text
    • https://www.skyline-recruiting.com/wp-content/plugins/super-forms/uploads/php/files/1822249ecfa87a3dea02007784da514c/45446879312.pdfIn PDF document text
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/606tlb0b01qsd89ke4um3852i4/7781927366.pdfIn PDF document text
    • https://lastcallslc.com/wp-content/plugins/super-forms/uploads/php/files/927588156218cf5eb85865ca651f57ae/65810447398.pdfIn PDF document text
    • https://bamfieldrental.com/userfiles/file/mebeza.pdfIn PDF document text
    • http://www.cheapmotorcycleinsurancepa.com/wp-content/plugins/super-forms/uploads/php/files/hhhrh1gbqsgha136rmsgjfbgs7/xafigofudubibufojebopuke.pdfIn PDF document text
    • https://stagerightstaging.com/wp-content/plugins/super-forms/uploads/php/files/5c33cba1776c42d64a073906531a31d5/12792493648.pdfIn PDF document text
    • http://strategie-online.net/catalogue_dynamique/file/13613240102.pdfIn PDF document text
    • http://www.saraviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f9d79d52b5---96045417758.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_off00010e2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E2A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012641.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12641 11328 bytes
SHA-256: 48668c374e67e26005db89f2a97ad648eceba0b66f30065c0a5ede9d8d2a836a
font_02_sfnt_off000140e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x140E2 17448 bytes
SHA-256: bc60b56de5adc078893cb2c88724bbed8d715a2c27f8dfb523551f4e20356036

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