Malicious PDF — malware analysis report

Static analysis result for SHA-256 8357c19b5772d513…

MALICIOUS

PDF

79.1 KB Created: 2021-09-21 12:34:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 980ea883124588121cd671d22988f784 SHA-1: 5936eca1b7210b16d05f2cb0b6641617e3d200ee SHA-256: 8357c19b5772d513a66c733ac0688c669bae406b4552ce688e52d25889716720
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous external URIs and links pointing to other PDF files hosted on various domains, many of which appear to be compromised CMS uploads or disposable hosting. This structure strongly suggests a link farm designed to distribute malicious content or phish users. The ML classifier also flagged this PDF with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

Heuristics 5

  • 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://medvor.ru/uplcv?utm_term=nfs+most+wanted+free+apk PDF link annotation
    • http://ecoevopublisher.com/files/upfiles/file/dejupamis.pdfIn PDF document text
    • https://juvelyrikoscentras.lt/Files/file/91673412425.pdfIn PDF document text
    • https://chung-pei.com/userfiles/file/fukeluwugepumuvivumipaxo.pdfIn PDF document text
    • http://watchimport.eu/userfiles/file/50122359001.pdfIn PDF document text
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/797703d59dd15f37c17da3025391a102/viramili.pdfIn PDF document text
    • https://bistro-8.com/wp-content/plugins/super-forms/uploads/php/files/a4e001238fc102273cbdbd316452eade/41250035765.pdfIn PDF document text
    • https://santaclara.com/wysiwygfiles/file/gifijamubokeb.pdfIn PDF document text
    • http://market-oborudovanie.ru/upload/file/49494264084.pdfIn PDF document text
    • http://hurtowniagrafit.pl/userfiles/file/sepoduwidanunuvovefomi.pdfIn PDF document text
    • http://thrifthelp.com/flash/thrifthelp.com/file/34371787491.pdfIn PDF document text
    • http://zatexpress.com/upload/userfiles/files/xovuzunesawogowure.pdfIn PDF document text
    • http://eunlocker.com/Images/Editor/file/27160155031.pdfIn PDF document text
    • https://rsun.pro/admin/ckfinder/userfiles/files/43540967074.pdfIn PDF document text
    • https://kristaldicarlo.com/userfiles/file/suradidazewovavokusemat.pdfIn PDF document text
    • https://dabanbep.tanglehadong.com/upload/files/43864889972.pdfIn PDF document text
    • https://behagi.eus/files/galeria/files/pefinerezigetodalinezimep.pdfIn PDF document text
    • https://cradlegold.com/wp-content/plugins/super-forms/uploads/php/files/c8huh806s7gd2b8boq7r8r08gc/rawokijupid.pdfIn PDF document text
    • http://fortlauderdalelimorental.net/wp-content/plugins/formcraft/file-upload/server/content/files/16132fba86943d---nugefonukes.pdfIn PDF document text
    • https://grupahatak.pl/admin/_fck_files/file/44444454351.pdfIn PDF document text
    • http://melly-incendie.fr/img_db/48051999468.pdfIn PDF document text
    • https://magerp.org/upload/files/70594263514.pdfIn PDF document text
    • http://flex-link.cn/uploadfiles/files/18939288731.pdfIn PDF document text
    • https://www.fyna.com.au/application/third_party/ckfinder/userfiles/files/77000989679.pdfIn PDF document text
    • http://zwickerfoto.hu/_user/file/febuzovefejitepono.pdfIn PDF document text
    • http://brandnewgoods.net/userfiles/file/vapodurogetobewu.pdfIn 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://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_off0000d271.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD271 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ea88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA88 10676 bytes
SHA-256: 6824fadc801d56143df939af8476e82158fae6438b9472dc7f9674f38c2a6b22
font_02_sfnt_off00010315.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10315 17156 bytes
SHA-256: b5b657508476ecc625167e981ce80922844ff0c6b03906730a44c0886a50e1ff