Malicious PDF — malware analysis report

Static analysis result for SHA-256 850572ac011fd8d8…

MALICIOUS

PDF

69.2 KB Created: 2021-09-30 20:54:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a5c713df3d5d332592f9da82658fec90 SHA-1: 7abb18dfc540974b1f89384b2a594b23e56e6169 SHA-256: 850572ac011fd8d8c3af8c578fcde0bfafe6638d573a92823a544188137e6a13
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as a malicious PDF by multiple heuristics and an ML classifier, with ClamAV detecting it as a phishing trojan. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users. The presence of embedded URLs and the PDF_URI heuristic indicate the primary function is to drive traffic to external, potentially malicious, sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://crewmak.ru/uplcv?utm_term=bmx+2+android PDF link annotation
    • https://cs-nippon-cp.com/mailmagazine/upload/files/mifuwapi.pdfIn PDF document text
    • http://www.giuseppe.ru/ckfinder/userfiles/files/tivuzelis.pdfIn PDF document text
    • http://studiovalecchi.it/userfiles/files/sanuguvoboboga.pdfIn PDF document text
    • http://asu78.ru/userfiles/file/zifojabetekenivo.pdfIn PDF document text
    • https://cosmopolitanhotel.eu/uploads/wysiwyg/files/valigumonunevuladaxoveni.pdfIn PDF document text
    • https://affordans.com/ckfinder/userfiles/files/36506211137.pdfIn PDF document text
    • http://mabifitness.it/userfiles/files/45939287807.pdfIn PDF document text
    • http://downtowncincyhotels.com/core_degree/admin/images/cms_imagesfiles/74225479546.pdfIn PDF document text
    • http://informerfitness.com/wp-content/plugins/super-forms/uploads/php/files/9e3e3a3185db4fa40a71be570bda1a25/lusowutanajivoxifeb.pdfIn PDF document text
    • https://www.vasutaszeneiskola.hu/ckfinder/userfiles/files/savutisug.pdfIn PDF document text
    • https://fiscalonline.eu/app/webroot/files/userfiles/files/rokudar.pdfIn PDF document text
    • https://studybrilliant.online/app/webroot/img/userfiles/file/4827348034.pdfIn PDF document text
    • https://foodvellythailand.com/upload/files/64026616491.pdfIn PDF document text
    • http://bitree.net/ckfinder/userfiles/files/43935867010.pdfIn PDF document text
    • http://wpscrm.in/uploaded_files/userfiles/files/doxapapopowo.pdfIn PDF document text
    • https://renetravel.ro/images/files/56284648081.pdfIn PDF document text
    • http://annabarons.com/files/files/76274832414.pdfIn PDF document text
    • http://cmorshomecareassociates.org/uploaded_files/userfiles/files/12056730292.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/kevuni.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613b5af5ce01b---joverogukasufabare.pdfIn PDF document text
    • http://paymentsbusiness.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16139c4959baac---norug.pdfIn PDF document text
    • http://pluimveebeurs.com/userfiles/file/vozikozagixisokunajij.pdfIn PDF document text
    • http://samtekelektrik.com/files/jajuxix.pdfIn PDF document text
    • 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_off0000b170.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB170 10240 bytes
SHA-256: f565afabf45909eb8b3f0aef279d61a65bfc2342dba652d1434d570e754abfb8
font_01_sfnt_off0000c869.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC869 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e07b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE07B 15448 bytes
SHA-256: dcb5dbbc6760c072af64375b329d5a938bde5aacb35ca77a6d7d154db4d65c27