Malicious PDF — malware analysis report

Static analysis result for SHA-256 99b91bedd80c8650…

MALICIOUS

PDF

85.4 KB Created: 2021-09-21 14:52:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d015a662efca518c49b3ec48601e7db6 SHA-1: 4f7b2056ddcfcc6f634a5102b3b0da75a1c145e1 SHA-256: 99b91bedd80c865040c0202e33f1c7c5b7748d6496829cd5b2b1b615040c3b6d
156 Risk Score

Malware Insights

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

The sample was detected as a phishing trojan by ClamAV and flagged by an ML classifier. It contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests the document's purpose is to host a large number of links on potentially untrusted domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 6

  • 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 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://blnk.eu/userfiles/files/ketizokowew.pdf In PDF document text
    • http://brbud.pl/userfiles/file/95693656452.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/34faaafe6d38c65f3c822798c3b2ac78/1448279754.pdfIn PDF document text
    • https://yodishit.com/uploads/userfiles/file/xominibusajadusu.pdfIn PDF document text
    • http://hamishehbaharcarpet.com/My_Project/Hamishe_bahar/ahar_img/files/polukefajob.pdfIn PDF document text
    • https://afanasyev-design.ru/wp-content/plugins/super-forms/uploads/php/files/06a0b8e07dfcc0de2c0675630898b169/84641257539.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/koramok.pdfIn PDF document text
    • http://eros-arena.de/eros/userfiles/file/gatinegorajivikusolok.pdfIn PDF document text
    • https://plantbiochem.com/ckfinder/userfiles/files/vurogamoba.pdfIn PDF document text
    • http://mateuszkucharski.pl/admin/file/14518802025.pdfIn PDF document text
    • http://khachsansapa.vn/webroot/img/files/10365919668.pdfIn PDF document text
    • http://vecsecity.info/editor_up/84094227500.pdfIn PDF document text
    • https://llbyggodesign.se/UserFiles/files/wedivufimaramutavumolixu.pdfIn PDF document text
    • http://clarklawtexas.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/perarim.pdfIn PDF document text
    • https://al-wesam.com/userfiles/files/fufilaforexikajuwimixu.pdfIn PDF document text
    • http://interwork.sk/userfiles/file/42927298692.pdfIn PDF document text
    • http://sskj.pl/userfiles/file/47185154713.pdfIn PDF document text
    • http://mtcnx.com/upload/fckimagesfile/48686779332.pdfIn PDF document text
    • https://restavracia02.com/userfiles/file/3469994388.pdfIn PDF document text
    • http://drivingtesttips.ie/fckeditor/userfiles/file/97860801581.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1613af98960bc9---99542616406.pdfIn PDF document text
    • https://hopefor.today/wp-content/plugins/super-forms/uploads/php/files/d01778243bcf132b667490fa9ac0171b/56677354191.pdfIn PDF document text
    • http://rideabikenews.com/user_img/files/jizufaxuwe.pdfIn PDF document text
    • http://wajl.net/img/file/2021910195147.pdfIn PDF document text
    • http://www.supair-lux.hu/ckfinder/userfiles/files/monumanogipujotaxawed.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=mts+app+for+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_off0000ec76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC76 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001048d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1048D 10304 bytes
SHA-256: 930722c0c8e0a6dff12e95b62acc3fca0214a387c3a1df9f4027598a6019e9a9
font_02_sfnt_off00011be3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BE3 17180 bytes
SHA-256: 5f1ba21fbb4f1ca27bfbe55dc4e4a42f6121e5e53a927493caab20e88e9caea5