Malicious PDF — malware analysis report

Static analysis result for SHA-256 1929953f56391491…

MALICIOUS

PDF

77.8 KB Created: 2021-09-06 03:57:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 214632af9b44ce308ceb82e1c0784d7c SHA-1: 5631de67fcc5c28f97e6cc712f8eda634451b858 SHA-256: 1929953f5639149198849cd2e722dea96dfa9afc375c5a576897562bff9020d2
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as Pdf.Phishing.Trojan. The file contains numerous links to compromised WordPress upload directories and disposable hosting, suggesting it is part of a link farm designed to redirect users to malicious sites. The embedded document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user consumption but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9829

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 http://ghemassagenhatban.vn/Images_upload/files/60824242640.pdf In PDF document text
    • http://pes.edu.mn/ckfinder/userfiles/files/24578608698.pdfIn PDF document text
    • https://yidinfo.net/wp-content/plugins/super-forms/uploads/php/files/4g37g9p2of4jlpak6nrfii1dp3/gebujon.pdfIn PDF document text
    • https://envomask.com/wp-content/plugins/super-forms/uploads/php/files/3c1d6919edad79d10287415b5e3bf38e/lolofenuvonukepugabapo.pdfIn PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/nmmnvh2kcm9v67nvkdeum124h6/zunew.pdfIn PDF document text
    • http://studioarchoggianiepartners.it/userfiles/files/xikenerigiwefetubap.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/ef190ebcbd751aeff62e54c08e00c254/93744671935.pdfIn PDF document text
    • http://hdurmuslar.com/images_upload/files/30837886433.pdfIn PDF document text
    • http://www.grundys.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607e2686463b5---tudewuparetovegezazavox.pdfIn PDF document text
    • http://hotelbelleepoque.bg/userfiles/file/vabolijafugo.pdfIn PDF document text
    • https://robertmatzuzi-massagetherapist.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160868bcb55949---68741300814.pdfIn PDF document text
    • http://tw-jia.com/uploads/files/202108171543387078.pdfIn PDF document text
    • http://dodici12.ru/wp-content/plugins/super-forms/uploads/php/files/97p0dlfn2foh4t1008gkk45cp3/tunotu.pdfIn PDF document text
    • https://www.potravinyav21.cz/ckfinder/userfiles/files/97949592492.pdfIn PDF document text
    • https://jollytime.ru/wp-content/plugins/super-forms/uploads/php/files/24a8466068ab81e4c1dc2f707f6bc946/lubovituta.pdfIn PDF document text
    • https://jooli.ru/ckfinder/userfiles/files/xudugujadus.pdfIn PDF document text
    • https://hiroyoung.com/data/files/10642140030.pdfIn PDF document text
    • http://bkbflooringusa.com/userfile/abbey/file/jelolemam.pdfIn PDF document text
    • http://mnogonomerov.ru/uploads/file/zuwefijumegijosese.pdfIn PDF document text
    • http://tulga.ru/editor/files/79667089270.pdfIn PDF document text
    • http://elitvorota.ru/f/file/3521127725.pdfIn PDF document text
    • https://hocaukhudothithanhphogiaoluu.com/asset/site/files/pazufowugejijazilijedile.pdfIn PDF document text
    • https://landi-bg.com/images/file/65231082374.pdfIn PDF document text
    • https://engineeredrepinc.com/wp-content/plugins/super-forms/uploads/php/files/918c43f10a61069cfe2900e1cff1c76c/50576816003.pdfIn PDF document text
    • https://caribemed.com/userfiles/file/16429465250.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/43274d63687b2ee6428f6864ad6d9070/wonomenuko.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=thrombocytopenia+in+neonates+pdfPDF 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_off0000cbb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBB0 11056 bytes
SHA-256: dcc48adb85e90ba39afa26d8fa032df9a997a9a7ae613d1ae1a33a09e695a53d
font_01_sfnt_off0000e50e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE50E 17420 bytes
SHA-256: a8fa1787f3d0475eb296a4052ecd426aacb4307c2c11448f5314f4dc8dad7880
font_02_sfnt_off000111cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111CD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1