Malicious PDF — malware analysis report

Static analysis result for SHA-256 131f8fa04a2f1f3b…

MALICIOUS

PDF

106.6 KB Created: 2021-10-08 02:20:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a23cc8141e3ac58fea9b666783fb94cc SHA-1: 8392f10fd9145e13b50ca99b49016b95193428d7 SHA-256: 131f8fa04a2f1f3bfd069346ab9a6a66c81e4920548d72ffcdca26863de30657
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to redirect users to malicious sites. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution. The document body is unreadable, but the heuristic firings and URL analysis are sufficient to infer the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

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://tssch.in/tssch/application/admin/uploads/file/73719513917.pdf In PDF document text
    • http://proxima-design.cz/files/file/vavup.pdfIn PDF document text
    • http://transcash.com/ci/userfiles/files/nupus.pdfIn PDF document text
    • http://mebelhotel.ru/userfiles/files/gevugojex.pdfIn PDF document text
    • http://podarox.ru/public/files/sutazozakamurexepusidop.pdfIn PDF document text
    • http://mclarenquartz.in/ci/userfiles/files/meletogapovedaxisudi.pdfIn PDF document text
    • http://cp-tournament.org/ckfinder/userfiles/files/bekazugeduwopu.pdfIn PDF document text
    • http://xhslsh.gdx.cn/ckfinder/userfiles/files/7967156569.pdfIn PDF document text
    • https://upaspor.com/resimler/files/50987459936.pdfIn PDF document text
    • http://nfrostov.ru/upload/files/kovipobuduba.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/haepl52dk2qrmfajj5jsi07ops/53243022392.pdfIn PDF document text
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/16131979a8d30e---61736802094.pdfIn PDF document text
    • https://bvphcn.bdata.vn/upload/files/wixukogegiligedimabutu.pdfIn PDF document text
    • https://equalitas.es/userfiles/file/99239577041.pdfIn PDF document text
    • https://ksmt.edu.np/assets/ckfinder/userfiles/files/63447372911.pdfIn PDF document text
    • https://kme.pl/global/app/webroot/uploads/file/16323003922325.pdfIn PDF document text
    • https://cuichi177.com/uploads/files/202110020124252598.pdfIn PDF document text
    • http://barrybusiness-crm.com/ressource/devis-photo/files/tuzajevov.pdfIn PDF document text
    • http://mouaumfb.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613dfc3563ed3---tozawakogo.pdfIn PDF document text
    • http://www.mustwalge.ee/data/content/files/6616391354.pdfIn PDF document text
    • http://print-resource.co.uk/ckfinder/userfiles/files/sifuwenena.pdfIn PDF document text
    • http://circuitoinsulargc.com/documentos/file/mekufuju.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=types+of+pagan+religionsPDF 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_off0001350c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1350C 21524 bytes
SHA-256: bc6a61c364bbc1d973aac073114bac2159762bc5c5ff0bae77896c26104160df
font_01_sfnt_off00016cba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16CBA 10512 bytes
SHA-256: 2f3c42e65e865e9b1e1a3a65a580cf52174b19680488dd2af67833f72cc62038
font_02_sfnt_off000184c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x184C9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1