Malicious PDF — malware analysis report

Static analysis result for SHA-256 efc18fef6feb2a1e…

MALICIOUS

PDF

87.0 KB Created: 2021-06-17 09:31:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 866883eaccbac30246936ad519d0ba49 SHA-1: 224fd36fe3188a576c8e133768d3502810e92cd5 SHA-256: efc18fef6feb2a1e7ba4c9f8b1be5cc2b0ea011e201e8b8163edefd58319dbcf
196 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress sites, suggesting a link farm designed to host and distribute malicious files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. The presence of embedded URLs and the nature of the heuristics point towards an attempt to trick users into downloading further malicious content.

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://krisoc.ru/uplcv?utm_term=learning+packets+sample PDF link annotation
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/160b2b52898192---97198863022.pdfIn PDF document text
    • https://abandassociates.com/ckfinder/userfiles/files/sasaliliravidajo.pdfIn PDF document text
    • https://vernadoc.com/wp-content/plugins/super-forms/uploads/php/files/1d1c9ca76f8a2577d62446ea36de1ef8/31471944099.pdfIn PDF document text
    • http://computergramm.com/userfiles/file/36453543272.pdfIn PDF document text
    • https://barcelonamedicalcenter.com/files/galeria/files/44234867607.pdfIn PDF document text
    • http://progfin.pl/userfiles/file/85374313571.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/jc6luv27tf1gm3696d79oqnoo2/69393327193.pdfIn PDF document text
    • https://amesmedicalservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cc66cac657---gununoxijiribodep.pdfIn PDF document text
    • https://deedpoll.sg/wp-content/plugins/super-forms/uploads/php/files/ed59e54afa6e1576dd3167d570b9354e/nedana.pdfIn PDF document text
    • http://mas.vacations/wp-content/plugins/formcraft/file-upload/server/content/files/1609811e24baf9---79208135688.pdfIn PDF document text
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bc7830ca3a---vazakesekixejubaruti.pdfIn PDF document text
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/9jiseddj9aaq83cdrmhvmcmso4/6008537628.pdfIn PDF document text
    • https://www.getfitcrew.com/wp-content/plugins/formcraft/file-upload/server/content/files/160999845030b2---fukane.pdfIn PDF document text
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/nlhi5psg2tc6gn0av1otelr8o3/nafegafafivez.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_off00011788.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11788 5256 bytes
SHA-256: 9cd42e840ef1ead36e7dfb5b74afc0c0a608cfcd8a86ae16edd50776eeb50312
font_01_sfnt_off0001295e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1295E 11040 bytes
SHA-256: a840a3b2233931bc9aeffd7dcea8bb9f037645cbb0b78278d408beebf54b3ab0