Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac4b0084d4c6cab9…

MALICIOUS

PDF

78.3 KB Created: 2021-06-13 02:23:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-01
MD5: a157148bb0e9046bf1c010345e8bea88 SHA-1: 2dfdff17a33f1e5e3000a124a52f2ff07a702d71 SHA-256: ac4b0084d4c6cab96e721d522528b7bb1ccdb450d5e9a826b17030930107c7f3
164 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://smidgel.ru/uplcv?utm_term=wifi+driver+for+802.11+n PDF link annotation
    • https://growlocals.com/wp-content/plugins/super-forms/uploads/php/files/deb380dfb96a6da812ae16e0c5e1cfa6/vakefi.pdfIn PDF document text
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f3d0f4b545---8337150745.pdfIn PDF document text
    • https://grafitpoint.ru/wp-content/plugins/super-forms/uploads/php/files/d74a867b9a2172e5a899a3be6bb117aa/beraf.pdfIn PDF document text
    • https://mymango.ru/wp-content/plugins/super-forms/uploads/php/files/1fe3c9b3503609d4951fd728aea44fc1/11973524988.pdfIn PDF document text
    • https://stopserv.ru/files/file/kobebitidumo.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/aad5f8023c650e1a47ad06fb32eff51f/78521469595.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c777a4b7b1---8482900085.pdfIn PDF document text
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b315e69f369---87004336908.pdfIn PDF document text
    • https://markzone.az/wp-content/plugins/super-forms/uploads/php/files/n77q7a2magmhc56269prb8k8p4/pijowuzixasufidemejafo.pdfIn PDF document text
    • http://raduzhniy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6afc12bbbc---waginuxinalozorodep.pdfIn PDF document text
    • https://dsodrecital.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4049591248---39747909639.pdfIn PDF document text
    • https://robotics-institute.com/wp-content/plugins/super-forms/uploads/php/files/btnthnjd16gjdmm32agslk8t2a/bufasuzufabafodasekatilek.pdfIn PDF document text
    • https://www.karenlovelee.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a950f171e2f---malososibigowax.pdfIn PDF document text
    • https://investainternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f5b2b08389---33257668870.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_off0000e901.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE901 5104 bytes
SHA-256: be21a94423d5b675ca0af1c6c822060e511d3b76bcbb6ab5cc57d758dcd9c2a2
font_01_sfnt_off0000fa97.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA97 21724 bytes
SHA-256: f52f58e9ab30547d49ea6f3389074d21d4e88056b0d1a789c3672b52f7c32a25