Malicious PDF — malware analysis report

Static analysis result for SHA-256 f1fcf28d7834f959…

MALICIOUS

PDF

104.5 KB Created: 2021-07-22 15:27:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-27
MD5: dfb6a03122dae3bb66c5bd9dfdfda380 SHA-1: 1e240f43268ca8562f5b4dfd4a5f615732239fab SHA-256: f1fcf28d7834f95966ede84f431fb57903218d9cab0a6bb4540f3a80da7c6d70
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised CMS upload directories, suggesting it's part of a link farm designed to manipulate search results or host malicious content. The presence of external URIs and a link farm heuristic strongly supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 http://busankid.com/webfiles/board/file///vesobogowad.pdf In PDF document text
    • http://cn-daomeng.com/upload/userfiles/files/25cddcb4eb90856091e26435714c1848.pdfIn PDF document text
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a33c0713bbf---92206927784.pdfIn PDF document text
    • http://teormech.ru/teormech/usrimg/file/65583275668.pdfIn PDF document text
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bdba49a72a2---subuxoxa.pdfIn PDF document text
    • http://alvirne88.com/clients/71477/File/33210217978.pdfIn PDF document text
    • https://drmarlenebothma.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160978332a24e1---2868456463.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1607c4e5aa81eb---74959650972.pdfIn PDF document text
    • http://www.luminicaambiental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b626c547b2b---38812898984.pdfIn PDF document text
    • http://www.hkqi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071342c60c19---84705720742.pdfIn PDF document text
    • https://pasarantogeldua.com/contents//files/36996247056.pdfIn PDF document text
    • http://eyupsifalibitkiler.com/resimler/files/wepatilovoxe.pdfIn PDF document text
    • https://daluxerealty.com/wp-content/plugins/super-forms/uploads/php/files/t3mb5cv28sh1at6r6epqh2ugs5/jizeruwebonopulobo.pdfIn PDF document text
    • https://schmitz.cz/res/file/likeno.pdfIn PDF document text
    • http://www.photobreak.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b8cbc6ea2a4---79360062147.pdfIn PDF document text
    • https://www.propertyfilevault.com/wp-content/plugins/super-forms/uploads/php/files/ed7e8a70c55eecf1edf0050a7b3a43a9/90059365198.pdfIn PDF document text
    • https://neoville.ru/wp-content/plugins/super-forms/uploads/php/files/312ba2b60ca6dd1d2dd616fa9e058f17/malakunolibaz.pdfIn PDF document text
    • http://nicosiacaffe.it/file/36626704325.pdfIn PDF document text
    • http://www.platformliften.info/wp-content/plugins/formcraft/file-upload/server/content/files/16097b2ca6ed55---726498811.pdfIn PDF document text
    • http://atol-res.pl/uploads/file/nubunelovubanew.pdfIn PDF document text
    • https://www.histoiresdegroupes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e108a44ff1---95695255903.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=history+of+embedded+systems+pptPDF 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_off00013656.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13656 10592 bytes
SHA-256: 3839612ec379be35688c2745732679fecdf6992c3d584894627f0cbbd02bbf2b
font_01_sfnt_off00014e5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14E5C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001666e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1666E 17256 bytes
SHA-256: b691f5fd3fbe95a40f3634394a4e9393ad29ba4514cc3c3fd6bf0676228a28f5

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