Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3ef0eac45810f7e…

MALICIOUS

PDF

95.2 KB Created: 2021-09-16 17:51:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 43e3b00726c704f6d1fd2dc8ec43415e SHA-1: cf7362625bc304fc6aa18e3b3128d439528bed24 SHA-256: a3ef0eac45810f7ea1644b19f0eb64fdc3e60b650fffaa9b6b563a6ebcf4eb18
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to disposable hosting or compromised WordPress sites, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. Although no scripts were explicitly extracted, the nature of the URLs and the heuristic firings point towards a malicious document, potentially leveraging embedded JavaScript for exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://synerhu.ru/uplcv?utm_term=android+ui+maker PDF link annotation
    • http://studiotecnicodambra.eu/userfiles/files/difasifexewatuxexivukaf.pdfIn PDF document text
    • http://apnschool.in/singhania/downloads/file/23461171152.pdfIn PDF document text
    • https://5of7edwardstreet.com/assets/media/files/37664243917.pdfIn PDF document text
    • http://cnmrobotics.com/files/files/kuxadawuj.pdfIn PDF document text
    • https://wic-net.com/userfiles/file/wetavara.pdfIn PDF document text
    • http://nitecoreromania.ro/files/file/49495240351.pdfIn PDF document text
    • http://sahcarpets.com/userfiles/file/79867717351.pdfIn PDF document text
    • http://andreuma.madteam.net/ckfinder/userfiles/files/65498266998.pdfIn PDF document text
    • http://marthomaiticherukole.com/userfiles/file/81144909877.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/161301ca7a312c---dafaxasutamale.pdfIn PDF document text
    • https://magerp.org/upload/files/pedilikupegob.pdfIn PDF document text
    • https://ural-aiti.ru/admin/ckfinder/userfiles/files/bijorev.pdfIn PDF document text
    • https://mchs.kz/userfiles/File/pivutukomosoned.pdfIn PDF document text
    • https://brawlcall.jordanadams.com/ckfinder/userfiles/files/37782465357.pdfIn PDF document text
    • http://aydinservis.com/ckfinder/userfiles/files/doraxikofijifopoveb.pdfIn PDF document text
    • http://swhos.com/upload/files/pefav.pdfIn PDF document text
    • https://masukpt1.com/contents/files/43150484165.pdfIn PDF document text
    • http://www.onegelha.com/wp-content/plugins/super-forms/uploads/php/files/53da641ab6996c5a44ffd2c533655e9c/rovetuvesaxatipatusafuso.pdfIn PDF document text
    • https://xn-----6kcabagcgfjsxjciriy6alkh6a7aqk.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/863bac45b090a5854219ef1cdb49a820/mawugus.pdfIn PDF document text
    • http://damutech.kz/upload/2021/09files/210908185137892766b5rgf.pdfIn PDF document text
    • http://playitdirect.ca/ckfinder/uploadfiles/files/kedusojuvu.pdfIn PDF document text
    • http://antik-cafe-bergen.de/wp-content/plugins/formcraft/file-upload/server/content/files/16140d522a3876---85503832872.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_off00011244.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11244 10268 bytes
SHA-256: 77b7ab47b66226b6f9c78c60b60a4a314a8c8c97964b31201962ce09a0ed0818
font_01_sfnt_off00012954.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12954 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014166.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14166 18064 bytes
SHA-256: 7c922966d86cc66366ac47abc86cb52e72c882d2de33d3ec53900f8c9134ac23