Malicious PDF — malware analysis report

Static analysis result for SHA-256 a6fbdbd9805922d8…

MALICIOUS

PDF

97.3 KB Created: 2021-09-16 19:44:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: f4193d331ad02cdd1ed8f7f647936f71 SHA-1: 67d7f5281689b09ce931c5b980482f6a1c941d97 SHA-256: a6fbdbd9805922d8b7d513c37b19eb8a31ee607fe25c40650e55cb468ba780a5
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the document functions as a link farm, directing users to multiple external websites, some of which are hosted on compromised CMS upload directories. The presence of numerous URLs, many pointing to potentially malicious or compromised sites, strongly suggests an intent to redirect users to phishing or malware distribution pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/fcakej7sv5dvs0551q16nj9sc4/66669824902.pdf In PDF document text
    • http://daydreamspin.com/userfiles/file/67957829604.pdfIn PDF document text
    • https://nangluongvada.com/uploads/files/karakinanalan.pdfIn PDF document text
    • https://komunalno.vrgorac.hr/files/vavugosipekuwuleso.pdfIn PDF document text
    • https://truongthanhco.vn/webroot/img/files/90069886223.pdfIn PDF document text
    • https://pavaniautismschools.com/wp-content/plugins/super-forms/uploads/php/files/6lqopc9ugfapli3jugb4l4t1sb/62186874215.pdfIn PDF document text
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/88afa87646b805c56ff5ee6b37d15996/59992048306.pdfIn PDF document text
    • http://tcsklife.com/filespath/files/20210904070833.pdfIn PDF document text
    • http://historia-bfured.hu/userfiles/file/roredavodezutad.pdfIn PDF document text
    • https://jamiatulbanat.in/wp-content/plugins/formcraft/file-upload/server/content/files/1613e229a7fb05---tuwezipesekopagekavijodu.pdfIn PDF document text
    • http://www.benvenutialmare.com/wp-content/plugins/formcraft/file-upload/server/content/files/161307411bb839---zawelebudozopelasorizo.pdfIn PDF document text
    • http://mcutech.net/upload/2021/09/file/16318042941952853296.pdfIn PDF document text
    • http://lj-group.cn/upload/files/4833097366.pdfIn PDF document text
    • https://sensesgrouphk.com/louis/STARKGROUP/ckfinder/userfiles/files/kurovazupowarafowedomo.pdfIn PDF document text
    • https://extremedriveline.com/ckfinder/userfiles/files/75426299111.pdfIn PDF document text
    • http://timnhanhonline.net/upload/files/28947369861.pdfIn PDF document text
    • https://ryokanclub.com/FileData/ckfinder/files/20210905_3783C625797A316B.pdfIn PDF document text
    • https://istruttorecinofilo.it/userfiles/file/wotogitojigulotapudag.pdfIn PDF document text
    • https://aadhaarretail.com/administrator/imagetemp/file/95329695508.pdfIn PDF document text
    • https://alpinashop.bg/files/96683559518.pdfIn PDF document text
    • https://magerp.org/upload/files/jusopogakujagovol.pdfIn PDF document text
    • https://leuphuotcamap.com/uploads/image/files/39773374509.pdfIn PDF document text
    • https://euforbiabulgaria.com/uploads/pages/files/najodotomazukozadesarab.pdfIn PDF document text
    • http://estatepie.com/files/userfiles/file/pixebovimivaxufuguxa.pdfIn PDF document text
    • https://www.artikel238.nl/emmwebbit/resources/ckfinder/userfiles/files/gozuze.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=mrs+funnybones+book+pdfPDF 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_off000112ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112EC 20232 bytes
SHA-256: 616293679447e72f354c8f17ba2a515a2f42af211b6d1c98f775c6a901d7bd92
font_01_sfnt_off000147a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x147A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015fb7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15FB7 10532 bytes
SHA-256: 026870a79107b80c57e6e585d4bdcbdc45e97244346b90f6927156b17edb7b40