Malicious PDF — malware analysis report

Static analysis result for SHA-256 838a9aad638d99b0…

MALICIOUS

PDF

94.8 KB Created: 2021-07-07 11:42:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: b58bfa94255eec24e080befe2e03db4c SHA-1: 5f35fc6cc7e121cd5e898ec018e1ce644543e5d4 SHA-256: 838a9aad638d99b0a9d883c1cc2627e5997069a8957cf0067002b4b49eaf628b
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple compromised WordPress upload sites and other disposable hosting domains. The embedded URLs and the nature of the heuristics strongly suggest this document is designed to deliver secondary payloads or lead users to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

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://anmoul.com/userfiles/file/fezoxonelaxerukawojekiv.pdf In PDF document text
    • https://www.groupenahno.com/wp-content/plugins/super-forms/uploads/php/files/8buh92uo0tnfdnhk1aibqm4gdf/kotubenetifoxared.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160ca5a3e0f8df---dosumitegesabunomaj.pdfIn PDF document text
    • https://genesisbehaviorcenter.com/wp-content/plugins/super-forms/uploads/php/files/3d44a37359b8254df821b9cfdc01e738/90199691692.pdfIn PDF document text
    • https://longhoang.vn/upload/files/kulazotifotoxipogapez.pdfIn PDF document text
    • https://lcd96.ru/wp-content/plugins/super-forms/uploads/php/files/038e9433854d7a2d3e7a67dca9a8eaa0/kazipibaliwi.pdfIn PDF document text
    • https://www.bakirkoytemsilcisi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607eaa58d7c03---xatufodumomixod.pdfIn PDF document text
    • http://mdc.ir/ckfinder/userfiles/files/vugemut.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160878cd3a7b66---zerunebifipodofexed.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c39a941138a---refeloz.pdfIn PDF document text
    • http://salonlomi.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160807b06e9296---29855928466.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/1609e466f48083---ruruno.pdfIn PDF document text
    • https://www.adilaltinsoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cb770ec910---ratito.pdfIn PDF document text
    • http://verkoop-je-wagen.be/wp-content/plugins/formcraft/file-upload/server/content/files/160aba7caf22bb---73872516131.pdfIn PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad7ab3d4c6d---71929816720.pdfIn PDF document text
    • http://associacaoguainumbi.org.br/wp/wp-content/plugins/formcraft/file-upload/server/content/files/1608844eb73111---62279147603.pdfIn PDF document text
    • http://dailygiasi.com/uploads/userfiles/file/19869312065.pdfIn PDF document text
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/fab65b58b0d5011227bd2f6323cd8221/selifiwadokebebil.pdfIn PDF document text
    • http://influences-vegetales.eu/assets/Image//files/39356007386.pdfIn PDF document text
    • https://bkht.vn/userfiles/file/99990756041.pdfIn PDF document text
    • https://preprodpcb.com/userfiles/files/siwex.pdfIn PDF document text
    • http://fashioncenterpoint.com/wp-content/plugins/super-forms/uploads/php/files/1efd47495a29004a655ed26c6dec1638/77372274701.pdfIn PDF document text
    • http://furkansigorta.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160c99aac79d92---sakijobisip.pdfIn PDF document text
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16080ce046bf05---wuzijovumibozitupaxeni.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=when+will+tax+refunds+be+released+2020PDF 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_off00010f60.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F60 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012777.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12777 10996 bytes
SHA-256: 5a9ef1ecb788e8f12e07176796149e2bf5ff560bad4be738b4caf0fda7bef636
font_02_sfnt_off00014103.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14103 17108 bytes
SHA-256: e9ae8f0a58c1754df4397bbc354ec5a80a484dedcedf335afdaa7e60b6f28ede