Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d3193b2258ef4d…

MALICIOUS

PDF

80.2 KB Created: 2021-09-19 03:07:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: d021b7979dd4399b52d9b1911a59b17e SHA-1: cccacccb53b540f7175451eaa4df06221e5be1cd SHA-256: 81d3193b2258ef4dfca7c720e552d888d3aac830fedf485bd2642ba91f038536
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. Heuristics identified the document as a link farm, with numerous external URIs pointing to potentially compromised or disposable hosting sites. The presence of multiple PDF links and the 'utm_term' parameter in one URL suggest an attempt to direct users to malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://www.sherpachristain.org.np/ckfinder/userfiles/files/70394860679.pdf In PDF document text
    • http://perchegouet.com/ckfinder/userfiles/files/53291243446.pdfIn PDF document text
    • http://gloteckr.com/upload/editor/file/gufuno.pdfIn PDF document text
    • https://spandoekland.nl/userfiles/file/36914686332.pdfIn PDF document text
    • http://theseadiaries.com/ckfinder/userfiles/files/21070128106.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1612fdf2b2e8c2---zukakabibakidugi.pdfIn PDF document text
    • http://sdsenlex.com/upload/files/94921145538.pdfIn PDF document text
    • http://traslochimontalto.it/userfiles/files/74561021687.pdfIn PDF document text
    • https://www.sesc-am.com.br/Selecao/ckfinder/files/30669590523.pdfIn PDF document text
    • http://max-metal.pl/gfx/file/batowokovejopirijudi.pdfIn PDF document text
    • http://conwaychristian.org/wp-content/plugins/formcraft/file-upload/server/content/files/16131258f5a538---viwoxe.pdfIn PDF document text
    • http://allycatering.com/userfiles/potatave.pdfIn PDF document text
    • https://betentour.com/sites/default/files/file/xenumumozufupi.pdfIn PDF document text
    • http://servicedental.it/userfiles/files/kexux.pdfIn PDF document text
    • http://bloemenwinkelindex.nl/images/uploads/57584869517.pdfIn PDF document text
    • https://master.plus/wp-content/plugins/super-forms/uploads/php/files/5ee945949da8fd9dbd5b3098e6d86150/teden.pdfIn PDF document text
    • http://pamatudarbai.lt/ckfinder/userfiles/files/44818013709.pdfIn PDF document text
    • http://dharmapuridiocese.com/svnprojects/DHD/Source/images/files/2511637717.pdfIn PDF document text
    • http://train-in-japan.com/images/blog/file/lizirovezefosokise.pdfIn PDF document text
    • http://www.morrisjones.co.uk/EditorImages/file/gamizabenajowubid.pdfIn PDF document text
    • https://matricula.arendic.cl/files/78440023731.pdfIn PDF document text
    • http://kxzyjy.com/CKEdit/upload/files/wigonobuleboduxekikisizem.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=windows+activator+by+dazPDF 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_off0000d42a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD42A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ec3c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC3C 18112 bytes
SHA-256: 30436edcd7f850f5f533e17d2ef4f6d152ef834dd2f2d935a87cd7000b07f511
font_02_sfnt_off00011ae7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AE7 10644 bytes
SHA-256: 117e381c05379df56932e0e046aa275f2d9ae9330443d43e725f9fd00a9d0d17