Malicious PDF — malware analysis report

Static analysis result for SHA-256 634cb2311f3bdf1e…

MALICIOUS

PDF

64.3 KB Created: 2021-06-24 15:33:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: c3f58774b9f3151726b07205b084735c SHA-1: 9acffbab06ae5d9366b0cec2b1913d14e9edff62 SHA-256: 634cb2311f3bdf1ed0af014e59646d11571d7df27478660a67d7c38c1b9bbbf2
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm. The document body, though heavily obfuscated, suggests a lure related to 'isobars and isotherms worksheet answers'. The embedded URLs point to compromised or disposable hosting, indicating an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • 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://studiopros.com/userfiles/file/ In PDF document text
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/160725be3c6c7d---347599665.pdfIn PDF document text
    • https://amatnieks.lv/pictures/image/36101891094.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/1608c62d8ea9fe---48333257041.pdfIn PDF document text
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/160b6baae75c18---96043358317.pdfIn PDF document text
    • https://noddy.nu/images/file/28039906750.pdfIn PDF document text
    • https://technok.cz/wp-content/plugins/super-forms/uploads/php/files/9a9407628397ec805761c33a18825084/mizaxujegetirow.pdfIn PDF document text
    • https://bloomland.com/sites/bloomland.com/files/84152729984.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b1e4edd203e---70570560571.pdfIn PDF document text
    • https://pjkconstruction.ca/images/file/gokafokegoduduta.pdfIn PDF document text
    • https://renesens21.com/ressources/upload/files/tupisagaloz.pdfIn PDF document text
    • https://specialbrands.gr/wp-content/plugins/super-forms/uploads/php/files/3509ac233fdf3d0a97950aadf089fd04/43920225292.pdfIn PDF document text
    • http://ar-intl.net/wp-content/plugins/super-forms/uploads/php/files/v35d93u3te673pr668cqk5c4n5/56316672402.pdfIn PDF document text
    • http://arcomproltd.com/userfiles/file/fuboko.pdfIn PDF document text
    • https://www.criteriainvest.com.br/wp-content/plugins/super-forms/uploads/php/files/vsk69bjdc4ihvffnc9458rblar/56084805607.pdfIn PDF document text
    • https://www.femregenx.co.za/wp-content/plugins/super-forms/uploads/php/files/kk0sqft323sjoqg4fvvsaq2pkh/93682255344.pdfIn PDF document text
    • http://www.northeastmarquees.com/wp-content/plugins/super-forms/uploads/php/files/6a6e9a3b22a2a7e2c0e8d423b738308e/43919016652.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=isobars+and+isotherms+worksheet+answersPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000beca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBECA 5264 bytes
SHA-256: 861182b5c6377ee92a9eff50679f8a769af95acd2d7c9d8c129ccf0044356994
font_01_sfnt_off0000d092.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD092 10452 bytes
SHA-256: f9b6da1d79aa740c64403ee9c304547957ee40d6db6060cbd48757f9223d2709