Malicious PDF — malware analysis report

Static analysis result for SHA-256 81c546a06b2411e6…

MALICIOUS

PDF

87.0 KB Created: 2021-07-25 09:32:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 21b7a29cfe38979194d3a4c57be535a2 SHA-1: f6be6452485e1d3abee119bb91aee94d458adefd SHA-256: 81c546a06b2411e6ecfb9ede77a97c2722cdca7c932a5ae2984f689b4cc277c9
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal that the document contains a link farm pointing to compromised WordPress upload storage and disposable hosting, suggesting a phishing or malware distribution lure. No scripts were extracted, but the presence of multiple external URLs on compromised sites strongly suggests an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9904

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://szpital-sulecin.pl/images/fckfiles/file/vigerivadumatosenoxireni.pdf In PDF document text
    • https://www.ibyservice.com/wp-content/plugins/super-forms/uploads/php/files/0b2a5b54e593eee9c126b28e9762fd1c/mejepaxexizuwelugosa.pdfIn PDF document text
    • https://alsultantrading.ae/userfiles/files/dagevugomawigezav.pdfIn PDF document text
    • https://aslimitada.com/userfiles/file/sitotopepitirigo.pdfIn PDF document text
    • https://qfuse.it/images/uploaded_files/ckfinder/files/1625428586_19a43c85a3.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ccfb757dae1---72804284111.pdfIn PDF document text
    • https://gbagencement.fr/uploads/file/xazufemageruketofiponujo.pdfIn PDF document text
    • http://bannermaul.com/userData/board/file/dofezeb.pdfIn PDF document text
    • http://diagnosticaedilizia.com/userfiles/files/2434200203.pdfIn PDF document text
    • https://alphacleanwashing.com/wp-content/plugins/super-forms/uploads/php/files/3c61899682f10c0bb42ad342e3028f22/xululajupupozidiwumerif.pdfIn PDF document text
    • https://arerp.kr/data/file///10447774145.pdfIn PDF document text
    • http://zbraneklapka.cz/ckfinder/userfiles/files/gaduwokabagugefib.pdfIn PDF document text
    • https://www.northernillumination.com/wp-content/plugins/super-forms/uploads/php/files/478c9818a2d6ddb8fa297c0d73adb37d/bizuronadu.pdfIn PDF document text
    • https://jclifeschools.org/wp-content/plugins/super-forms/uploads/php/files/41de3d3e891dfe1abad1859ffe50d2e6/47002365708.pdfIn PDF document text
    • https://alutat.com/data/file/derovavaworojizikatudetad.pdfIn PDF document text
    • https://glasschneider.koeln/wp-content/plugins/super-forms/uploads/php/files/kruvik56v2jhpjuhjqjslcjjpe/lixapat.pdfIn PDF document text
    • http://lalitas-thaimassage-spa.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607fce980c4e1---nepitavorujom.pdfIn PDF document text
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/7a6356edda2777cc36586510de4edbee/18439793023.pdfIn PDF document text
    • https://hzautomatisering.nl/userfiles/file/25108176084.pdfIn PDF document text
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/160728e1b6e922---duwugokilatexiwabimo.pdfIn PDF document text
    • https://maugli24.ru/wp-content/plugins/super-forms/uploads/php/files/34202f20292201d1ffef667d0bdc1300/sujarelowajizasuwel.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fd609c755f---gelajiverunupepatiga.pdfIn PDF document text
    • http://cuiquji.net/d/files/gasobozajelepajukitawede.pdfIn PDF document text
    • http://ambulatorioveterinariocigliano.com/userfiles/files/59539961844.pdfIn PDF document text
    • https://drinkpoint.com/uploads/files/giriwizoramixawa.pdfIn PDF document text
    • https://getlovebooks.com/wp-content/plugins/super-forms/uploads/php/files/8b121931b45bd8650c64faddc9e94ec2/sepesuku.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+replace+hard+drive+toshiba+satellite+c55PDF 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_off0000ef31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF31 10924 bytes
SHA-256: 454aafb6a3dd744581092bfb88f54df8ce6f23deb06ceb77d75db176831af3df
font_01_sfnt_off00010877.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10877 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012089.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12089 16908 bytes
SHA-256: 04f3c0e28b8fac1242178e3ed0d601a44005b81176297789e18d619ae90b11a1

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