Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f2a61da37f894ad…

MALICIOUS

PDF

100.6 KB Created: 2021-06-09 23:13:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 04ba92588bedbb1f1abd9a03e840be39 SHA-1: 8dfae2130bd995c2f03cd412a17a6d697813145c SHA-256: 3f2a61da37f894ad1efdaec20a17b0c255ce911332fdfb9390076f6b90c8dc9a
164 Risk Score

Malware Insights

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

The PDF file is identified as malicious by ML classifiers and ClamAV, and contains numerous links to compromised WordPress sites and other disposable hosting. The document body, though heavily obfuscated, suggests a lure related to 'Amoeba sisters mitosis worksheet answers', indicating a phishing or social engineering attempt to trick users into downloading further malicious content. The presence of embedded URLs and link farms points to a distribution mechanism for malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://archism.ru/uplcv?utm_term=amoeba+sisters+mitosis+worksheet+answers PDF link annotation
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16089c0208a8ab---lavatamuvagadi.pdfIn PDF document text
    • http://franzoesischebulldoggen.eu/userfiles/file/bubex.pdfIn PDF document text
    • https://www.scilights.com/wp-content/plugins/super-forms/uploads/php/files/40aee1597951d5242f18fadc0d7aa2ef/bomunudujosidafotur.pdfIn PDF document text
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f41a18c22d---41380416044.pdfIn PDF document text
    • http://strahovka66.ru/userfiles/file/bulesalokubiburolubi.pdfIn PDF document text
    • http://ascensionchina.com/userfiles/file/88229017714.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073c3fff3ac1---wajokenibumog.pdfIn PDF document text
    • http://asea-admin.com/_userfiles/file/20210510035614.pdfIn PDF document text
    • https://stpetejazz.com/wp-content/plugins/super-forms/uploads/php/files/t1s8lel7srpiv64706e0g3b1ta/46263623277.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac37f628007---77690235777.pdfIn PDF document text
    • http://www.risingstars.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160a8636b14c4d---tusizubibabusefo.pdfIn PDF document text
    • http://www.driftime.ee/wp-content/plugins/formcraft/file-upload/server/content/files/160ba2e7005871---pikigalaxinenoletur.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_off00014e78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14E78 5180 bytes
SHA-256: 9ef4a92fed6378b756995a8ce20b661305d5c20832b7541477828beb088060c9
font_01_sfnt_off00015ff7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15FF7 10912 bytes
SHA-256: 879366b9fb90aefecdc8c718f10c3da767f4141bf7c3df402e418eca6cf213c1

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