Malicious PDF — malware analysis report

Static analysis result for SHA-256 3cb71d24745c7ea0…

MALICIOUS

PDF

71.0 KB Created: 2021-09-05 02:32:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 21c0beb089d86a84c276ce4f8372d4c2 SHA-1: ae4174c0cbd50f6bc1ee2d0f5c8eb0052569711e SHA-256: 3cb71d24745c7ea00ac980451323c9e180e650a2d0f685177c39704fc8e42833
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple heuristics indicating it's part of a link farm, with several pointing to compromised CMS upload directories and disposable hosting. The ML classifier and ClamAV detection strongly suggest malicious intent. While no scripts were explicitly extracted, the PDF structure and embedded URIs are indicative of a phishing or malware distribution lure, likely leading to a second-stage download.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9893

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
  • Clickable URI points to raw IP address medium PDF_URI_IP_LITERAL
    PDF contains a clickable HTTP(S) action whose host is a literal IPv4 address. Legitimate documents normally link to named domains; raw-IP destinations are common in disposable phishing and malware-delivery infrastructure.
  • 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://coytex.net/ckfinder/userfiles/files/26549866194.pdf In PDF document text
    • http://www.cbs-emballages.com/upload/file/wirixoginulusibexidezote.pdfIn PDF document text
    • http://www.corazondelsol.es/ckfinder/userfiles/files/giwibufesisobagikisunem.pdfIn PDF document text
    • http://train-in-japan.com/images/blog//file/xujesalazivuwesumafuj.pdfIn PDF document text
    • https://euroroma-bg.org/files/file/14878327137.pdfIn PDF document text
    • https://michelbarbot.com/upload/files/61030148970.pdfIn PDF document text
    • https://vetranhtuongmamnon.vn/wp-content/plugins/super-forms/uploads/php/files/do3n3le5kcsndu9bk0daglimr8/70767987097.pdfIn PDF document text
    • https://ddshower.com/ckfinder/userfiles/files/gikesunimijepawewesubolu.pdfIn PDF document text
    • http://beerskiboot.com/img/upload/file/tuzaxejawosifira.pdfIn PDF document text
    • https://exxontel.com/file/tulupizites.pdfIn PDF document text
    • https://digireg.cn/upload/rejizagozuk.pdfIn PDF document text
    • http://gojjang.com/uploads/files/36311482477.pdfIn PDF document text
    • http://beloit1962.com/clients/8/83/8368a4f838dea3176655029ae9e337da/File/89637780934.pdfIn PDF document text
    • https://lakeshoresmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/qscbd2gpglstnf66tqti8m81b4/difisum.pdfIn PDF document text
    • http://supermarketdv.ru/files/file/91316910277.pdfIn PDF document text
    • https://alianzatours.com/imagenes/file/86367939796.pdfIn PDF document text
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/e94df933533694e4f9b5cab9c5559b82/feboximumogilo.pdfIn PDF document text
    • http://babywagen24.de/userfiles/file/51003908160.pdfIn PDF document text
    • http://federalwayhighschoolclassof1970.com/clients/8/8c/8ce2019516a67423f07d8eefa67dd611/File/99841210908.pdfIn PDF document text
    • http://www.gleason.com.au/application/third_party/ckfinder/userfiles/files/23974766971.pdfIn PDF document text
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d83c31316e---xumubezigazap.pdfIn PDF document text
    • http://www.expo-hotel.com/english/wp-content/plugins/formcraft/file-upload/server/content/files/160907305974e9---sigoranidepamizixabel.pdfIn PDF document text
    • http://quatang3t.com/upload/files/35413365196.pdfIn PDF document text
    • http://104.156.58.56/~web2inbox/wp-content/plugins/formcraft/file-upload/server/content/files/160a598f7ebc93---27682360535.pdfPDF link annotation
    • http://ambulanceservice.pl/userfiles/file/negodogudexavesegoparular.pdfIn PDF document text
    • https://www.highlandernepal.com/assets/ckfinder/userfiles/files/ludetukaxawumili.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=business+model+pdf+free+downloadPDF 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_off0000b7b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB7B9 14980 bytes
SHA-256: 71b4426846e8bd81bdedcf5ec21b47db158b6ef05e2fc897adec9f7a02869c44
font_01_sfnt_off0000dd62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD62 10800 bytes
SHA-256: 35959118abd6257c05c9687c3ae8ece2a1e571df4531354f21759010f0ccf27e
font_02_sfnt_off0000f649.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF649 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1