Malicious PDF — malware analysis report

Static analysis result for SHA-256 731c70b66830832c…

MALICIOUS

PDF

139.9 KB Created: 2021-08-20 10:50:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: c6440a41749c6e6f989034e062baf956 SHA-1: 0671d26232647f47ff6603d7ce7e12a8b5670753 SHA-256: 731c70b66830832c07501556024235061d79c76bf71a05ef74473e4a9231fb49
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to external websites, including those hosted on compromised CMS platforms. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware through these links. The document body is heavily obfuscated and unreadable, providing no direct user-facing content, but the heuristic firings clearly point to a link farm strategy.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9712

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://fw-simple.com/uploads/files/5526221515.pdf In PDF document text
    • https://dacsanmyhuongbeti.com/app/webroot/files/images/pages/files/jixedixosalegik.pdfIn PDF document text
    • https://luathoanghuy.com/uploads/files/16711577633.pdfIn PDF document text
    • http://ehoron21.mn/uploads/files/66796502832.pdfIn PDF document text
    • https://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070c47673a18---mepudemefid.pdfIn PDF document text
    • http://pamatudarbai.lt/ckfinder/userfiles/files/tuludolipomarulos.pdfIn PDF document text
    • http://thanhtindesign.vn/uploads/image/files/vuboragorez.pdfIn PDF document text
    • https://apz-arte.com/ckfinder/userfiles/files/13650909243.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/645234ecf353424302932d8de3180cfd/gilujufaxeguxigeg.pdfIn PDF document text
    • https://asiatravel.kg/wp-content/plugins/super-forms/uploads/php/files/abfc51bbbb2076c060fb5e58ab9967e8/56814683917.pdfIn PDF document text
    • http://zerosquareonline.com/file/48334243857.pdfIn PDF document text
    • http://geofer.eu/userfiles/files/8683461461.pdfIn PDF document text
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/16077e1fabdcb1---vigufibewexexegefu.pdfIn PDF document text
    • https://debcopharma.com/userfiles/file/46908246954.pdfIn PDF document text
    • http://bidmitt.com/img/files/file/30268537771.pdfIn PDF document text
    • https://wildnaturetravel.com/File/lakoribekojurupawegajejet.pdfIn PDF document text
    • http://alkanboya.com/files/file///41310677383.pdfIn PDF document text
    • https://xn--80aggmy8c6c.net/UserFiles/File/soledu.pdfIn PDF document text
    • http://astorandblack.net/emailer/userfiles/file/kamada.pdfIn PDF document text
    • https://www.lamuccacompany.com/wp-content/plugins/super-forms/uploads/php/files/6c73d7d4027777a69c569bab3ae3d88d/savovekaved.pdfIn PDF document text
    • https://mackbeks.com/files/file/sepopibiseluxovopore.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/1609e6f094b993---metabemozode.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=ejercicios+de+refuerzo+1+eso+potencias+y+raices+elementales+resueltosPDF 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_off0001ba77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1BA77 11220 bytes
SHA-256: 1c14ea27d55b68b6e317a91c68c574c64afa9d066f6e8cb3b6140edd3b39059f
font_01_sfnt_off0001d4d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1D4D2 19120 bytes
SHA-256: b746b8b3f4f4fcb6476e4a1f8843a9bb48af6cc705ad717f93ecb09273a90fca
font_02_sfnt_off0002058b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2058B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1