Malicious PDF — malware analysis report

Static analysis result for SHA-256 835f8c2435e64335…

MALICIOUS

PDF

80.4 KB Created: 2021-09-12 15:11:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: fadaf6f8a978c3aa86ae79ebb15c2a98 SHA-1: 6638b194b16e5ceb1a1875109b29ee98fbacd480 SHA-256: 835f8c2435e64335fb6e07d2504e1c9e97ebdc8959195d5b37ca897901c9b833
196 Risk Score

Malware Insights

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

The sample is a PDF document flagged by ClamAV as a phishing trojan. Heuristics indicate it is a link farm, with many URLs pointing to potentially compromised websites or disposable hosting. The 'SE_CLICKFIX' heuristic specifically identifies a social engineering attack that instructs the user to press Win+R or paste a command into a terminal, a common technique to bypass macro restrictions and execute malicious code. While no scripts were explicitly extracted, the presence of embedded URLs and the nature of the ClickFix heuristic suggest the document is designed to lead the user to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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
  • ClickFix social engineering attack high SE_CLICKFIX
    Document instructs the user to press Win+R or paste a command into a terminal — consistent with ClickFix attacks that bypass macro restrictions by tricking users into running malicious commands directly
  • 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://servicedental.it/userfiles/files/daruwirabagisabobupepilet.pdf In PDF document text
    • http://popmetre.com/news/files/pewuva.pdfIn PDF document text
    • https://glasschneider.koeln/wp-content/plugins/super-forms/uploads/php/files/kqmsls0m5h3uos7hj1ursvvl6o/47315651906.pdfIn PDF document text
    • http://eventclub.pl/userfiles/file/42695069332.pdfIn PDF document text
    • https://msiutilities.net/documents/remalamonise.pdfIn PDF document text
    • http://aliguoriarchitetto.eu/userfiles/files/batatepul.pdfIn PDF document text
    • http://www.hj-bouwt.be/wp-content/plugins/formcraft/file-upload/server/content/files/16137fd8345bcb---gakafogizorukok.pdfIn PDF document text
    • https://chameleoncoupons.com/adgprocessing/uploads/files/zisijobaxuwem.pdfIn PDF document text
    • http://lamekatus.com/uploads/ckeditor/files/32956977839.pdfIn PDF document text
    • http://phaptangpgvn.net/app/webroot/upload/files/39068673000.pdfIn PDF document text
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16133488d0b21d---43081042480.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139b502cce40---21132826465.pdfIn PDF document text
    • https://samsunyapi.com/userfiles/files/ziviba.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/dbcb3cbb5da022130f937315295a8486/kuvinan.pdfIn PDF document text
    • http://denetimmusavirlik.com/userfiles/file/61899534293.pdfIn PDF document text
    • https://ahha.az/userfiles/file/83590760753.pdfIn PDF document text
    • http://kahounova.cz/userfiles/file/38983674361.pdfIn PDF document text
    • http://kriosispl.com/cote_dor_import/admin/ckfinder/userfiles/files/pamotesujobit.pdfIn PDF document text
    • http://divorcefinance.nl/uploads/file/23120950021.pdfIn PDF document text
    • http://lyzph.com/userfiles/file/Fl202109041559594415.pdfIn PDF document text
    • http://tubemakingmachine.com/uploadfile/files/56321952792.pdfIn PDF document text
    • http://tdvvietnam.vn/webroot/img/files/dibejazakorile.pdfIn PDF document text
    • http://profstil.az/userfiles/file/losujupinaximi.pdfIn PDF document text
    • http://spielundlicht.de/content_provider/documents/files/88788058590.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=how+to+switch+off+safe+mode+in+androidPDF 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_off0000d4c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C8 10772 bytes
SHA-256: 4933c9396e2e4da3ab8c5866cd54db98b352b23b6b98897e06286b53f2847543
font_01_sfnt_off0000ed66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED66 17892 bytes
SHA-256: 491626ce12066e898bfa8fda94246cd66b83cc8cbcdc645b2634cc9b9e8e475c
font_02_sfnt_off00011b93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B93 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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