Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4bb55819c1d370e…

MALICIOUS

PDF

71.0 KB Created: 2021-09-28 11:56:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 48078225c124c23f75090f87f03179d0 SHA-1: a9f41c79f100eff1489c78319dfc4ddab880129e SHA-256: a4bb55819c1d370e8f970b86d55544d126bfdbef0d1266aa99d64dda4318f2eb
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many URLs pointing to potentially compromised websites or disposable hosting. The embedded URLs, despite one being labeled benign, contribute to the overall pattern of directing users to external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/16135ad4f26d71---20852253933.pdf In PDF document text
    • https://x-leather.com/radsportfiles/file/26001467107.pdfIn PDF document text
    • https://vcvscr.cz/www/www/fckphotos/file/memejanowikaduwevel.pdfIn PDF document text
    • https://kenhquangcao.vn/uploads/files/mumitikefupiridetuz.pdfIn PDF document text
    • http://www.egavilanes.com/ckfinder/userfiles/files/vuxejinogakikevi.pdfIn PDF document text
    • https://huuphongplastic.vn/uploads/images/files/92815863418.pdfIn PDF document text
    • https://jechrina.gr/FCKeditor/userimages/file/87486172329.pdfIn PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133f1a24a71a---67023528648.pdfIn PDF document text
    • http://skrutit-probeg.ru/upload_picture/file/kifidanomoninijo.pdfIn PDF document text
    • http://chickendaylacrescenta.com/uploads/files/63884869022.pdfIn PDF document text
    • http://rubivina.com/Images_upload/files/39486290828.pdfIn PDF document text
    • http://chroscina.com/userfiles/file/velakumixelepafusig.pdfIn PDF document text
    • http://hyunsin.net/userfiles/file/20189795830.pdfIn PDF document text
    • https://ekoelprom.pl/public/images/editor/file/lepufumesanutinupejemo.pdfIn PDF document text
    • https://e-tta.com/app/webroot/userfiles/files/56002567432.pdfIn PDF document text
    • http://onelove.cz/file/jobowemuxas.pdfIn PDF document text
    • http://la-roofers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16134886189e50---palunutofupuxagevokik.pdfIn PDF document text
    • https://bushregenerators.com/userfiles/files/selojefub.pdfIn PDF document text
    • http://www.hkqi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141aa1836f1d---mubolisidijopaxalazuda.pdfIn PDF document text
    • http://jiin-torng.com/uploadfiles/20210924010249.pdfIn PDF document text
    • https://gccpay.net/wp-content/plugins/super-forms/uploads/php/files/06cdee408cd31c07e7411281ac5c08a0/watinovojipapupunugemiv.pdfIn PDF document text
    • http://sskj.pl/userfiles/file/fetijuziluzi.pdfIn PDF document text
    • https://arslanemlak.com/E/file/In PDF document text
    • https://uclerbaklava.com/resources/file/bipeti.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=how+can+i+check+wifi+password+on+my+phonePDF 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_off0000b3e6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3E6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cbf8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBF8 16064 bytes
SHA-256: 06307a33f7974d19813ebe3bd50db9158a63948e520d578bf61553180bb6339a
font_02_sfnt_off0000f493.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF493 11024 bytes
SHA-256: f48ce154d3b94a1a94d6736b11783816d2b90e350115f04f45dff7d8e4c96bf6