Malicious PDF — malware analysis report

Static analysis result for SHA-256 39fef97fef6ee818…

MALICIOUS

PDF

68.9 KB Created: 2021-10-03 20:36:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: bd1df72fc54e89d7dce49fff551e4f3b SHA-1: 0241376994175d470b3f8b80f32c7c8147c9f03e SHA-256: 39fef97fef6ee818e7ad7e1778bcc462ee79cee9cfc7485cd40e0fd65bc4f344
176 Risk Score

Malware Insights

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

The PDF is identified as a phishing lure due to its image-only nature and embedded clickable links. Several heuristics indicate that the document links to compromised CMS uploads, specifically WordPress sites, which host further malicious PDFs. The ML classifier and ClamAV detection strongly support its malicious classification.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9950

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
  • Image-only document with action trigger (screenshot lure) medium PDF_IMAGE_LURE
    PDF has 1 image(s), only 0 text block(s), carries a click-outward action, and is only 68 KB — typical shape of a phishing lure where a full-page screenshot hides a clickable button that launches or submits to an attacker URL.
  • 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://chanakol.com/ckfinder/userfiles/files/22987505431.pdf In PDF document text
    • http://hsi-international.com/ckfinder/userfiles/files/nonevaroke.pdfIn PDF document text
    • https://nomortiga.com/contents/files/dafazuvaridodinagokopized.pdfIn PDF document text
    • http://capmar.eu/userfiles/file/gesapimazo.pdfIn PDF document text
    • http://jjinline.org/file_upload/file/90047473972.pdfIn PDF document text
    • https://brillimet.com/uploads/files/202109301108502355.pdfIn PDF document text
    • http://avanti-kuhni.ru/upload/files/169103249.pdfIn PDF document text
    • http://micruts.org/userfiles/file/somiseximutubilejera.pdfIn PDF document text
    • http://www.dadosefatos.net.br/wp-content/plugins/formcraft/file-upload/server/content/files/1614cccb2a3b37---nagufe.pdfIn PDF document text
    • http://vinaktv.com/storage/ckfinder/files/17446820887.pdfIn PDF document text
    • https://andana.us/files/files/91910768755.pdfIn PDF document text
    • http://dalieuht.com/app/webroot/uploads/files/dekovujixesufeki.pdfIn PDF document text
    • https://hankilfood.com/upfile/files/22313759474.pdfIn PDF document text
    • http://byecook.com/ckupload/files/11163951263.pdfIn PDF document text
    • http://masan315.net/board/imagefile/file/60145130802.pdfIn PDF document text
    • http://tdsns.ru/userfiles/file/wajoxuze.pdfIn PDF document text
    • https://shrmivirtual.org/wp-content/plugins/super-forms/uploads/php/files/28875f05a8db69b2810073371ef1ffce/zukakuwajamikenimuw.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161338cf62d212---mebuvasobeso.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613549a172939---fosazopilurox.pdfIn PDF document text
    • http://technimexvn.com/images/ckeditor/files/72644036996.pdfIn PDF document text
    • http://hstechno.com/userData/ebizro_board/file/sixoda.pdfIn PDF document text
    • http://curry-box-deluxe.de/userfiles/file/netopopefib.pdfIn PDF document text
    • https://osiindia.org/ckfinder/userfiles/files/futazisozirezuzesefojos.pdfIn PDF document text
    • https://indiantiffin4me.com/nbloom/fckuploads/file/34813219186.pdfIn PDF document text
    • https://aucordechasse.fr/vosImages/70120707478.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=how+many+cards+in+a+cards+against+humanity+deckPDF 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_off0000b066.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB066 14416 bytes
SHA-256: 2b0711cb387eba72ebf7d47de3793e1b63f92328b32de7671afabdabc13d6643
font_01_sfnt_off0000d41b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD41B 11156 bytes
SHA-256: bf784bd8a3aa9e48a64fad60f7ad35ca607ac14ac30a4b04b8dc2d13b936743d
font_02_sfnt_off0000eddf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDDF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1