Malicious PDF — malware analysis report

Static analysis result for SHA-256 31b79c34b3936f88…

MALICIOUS

PDF

73.8 KB Created: 2021-09-06 02:13:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 21c81adca3caaa1dbaef4a92da1fb1af SHA-1: ab025ac462183b3ec96ec1cb4c56fdcb38376c8a SHA-256: 31b79c34b3936f8891efe816d8638b77a76a79c2c55649eb3d34a26f00df79d4
156 Risk Score

Malware Insights

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

The PDF contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware distribution. No scripts were extracted, but the structure and URL patterns are indicative of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://xn--22ck6bdp5cach0mc23a.com/ckfinder/userfiles/files/fixuzuzilixag.pdf In PDF document text
    • http://duda-tech.pl/dudatech/upload/file/wafuvem.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/ul9k42sa59hfuti5hh097680g2/jotadejexodef.pdfIn PDF document text
    • http://helder-effect.nl/userfiles/file/24484876112.pdfIn PDF document text
    • http://zaun-produzent.de/userfiles/file/81055204134.pdfIn PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/16097cd805c538---jovinowu.pdfIn PDF document text
    • https://emmaushuis.org/pages/ziwilotabebobutatidasi.pdfIn PDF document text
    • http://hotelrealerimini.it/userfiles/files/98718430840.pdfIn PDF document text
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160911e4626cf9---bekaxisotoliregulatuzip.pdfIn PDF document text
    • http://heatexchangersolution.com/upload_fck/file/2021-8-9/20210809192325508331.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/88258700482.pdfIn PDF document text
    • https://perfecthospital.org/FCKeditor/file/12580296721.pdfIn PDF document text
    • http://coreaad.com/DreamDataUpload/file/6045633344.pdfIn PDF document text
    • https://stallion-international.com/userfiles/file/44012338485.pdfIn PDF document text
    • http://cayxaotamphan.net/userfiles/image/file/sozaxefuniwu.pdfIn PDF document text
    • http://phanphoiongnhuahoasen.vn/upload/files/zegiwemafo.pdfIn PDF document text
    • https://limpjet.com.br/wp-content/plugins/super-forms/uploads/php/files/cd58be94a45deadf7c0016c4e541d1d5/gifobepufubojepepetela.pdfIn PDF document text
    • http://gniortho.com/files/Upload/file/94644729262.pdfIn PDF document text
    • https://dodatnojamstvo.com/userfiles/file/24106326785.pdfIn PDF document text
    • https://btsis.com/upload/ckfinder/files/kopuzejopomodopuriwugige.pdfIn PDF document text
    • http://romengo.com/ckfinder/userfiles/files/ruzak.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/v08n7d1ci38ah3jq0b7rb66b9f/xinokoperafuko.pdfIn PDF document text
    • http://sz-nuoyi.com/Upload/file/2021080502054994833.pdfIn PDF document text
    • https://namastehealth.in/wp-content/plugins/super-forms/uploads/php/files/f431q7er19ngm4dp5ok210jjo5/17097916734.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=ncert+chemistry+book+for+class+11+pdf+free+downloadPDF 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_off0000bd34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD34 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d54b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD54B 11344 bytes
SHA-256: a96e99657afe1aad904e65c5afe0f0bbce735dbcb95c85c266852a051202835c
font_02_sfnt_off0000efc0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFC0 16160 bytes
SHA-256: f9bfb46e80bd2bbfd2b8e757bc3ed02e519018144610644e14b628463d51b089