Malicious PDF — malware analysis report

Static analysis result for SHA-256 99ba51d80cae7a61…

MALICIOUS

PDF

77.6 KB Created: 2021-09-18 01:20:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3c86d80a7d178230ab7647d01a0351df SHA-1: cbb70a38d57ddb581c81a677d4b86b07675e511e SHA-256: 99ba51d80cae7a61e7ef778060d3fcad4084b758c6bf2b4c5a32d2c37fa2834e
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. It contains embedded JavaScript, which is often used to download further malicious content or redirect users to phishing sites. Several external URLs were extracted, some pointing to compromised WordPress uploads and others to disposable hosting, suggesting a link farm designed to obscure the ultimate destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9829

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://laibros.com/ckeditor/userfiles/files/lusozitifezokikejojadegil.pdf In PDF document text
    • https://vibangthuaphatlai.net/uploads/files/87924524132.pdfIn PDF document text
    • http://em-mould.com/ckfinder/userfiles/files/bokida.pdfIn PDF document text
    • http://gayaarchi.com/userfiles/file/20210907153231.pdfIn PDF document text
    • https://mcq.bmtinhoc.vn/InteriorWeb/images/images_news/files/belexitamafisexazalo.pdfIn PDF document text
    • http://younewstoday.com/task/userimages/file/fijojovoton.pdfIn PDF document text
    • http://www.phsdcenter.com/temp/js/ckfinder/userfiles/files/40177119700.pdfIn PDF document text
    • http://yangs-ns.com/ckfinder/userfiles/files/20210903222450.pdfIn PDF document text
    • http://studioingegneriavaragnolo.com/userfiles/files/fubeketaveletefilojenik.pdfIn PDF document text
    • http://feriaalainversa.com/uploaded/files/gowesonopaxegobalik.pdfIn PDF document text
    • http://kiiga.ru/userfiles/file/neropuxapaxubune.pdfIn PDF document text
    • https://fobh.net/userfiles/files/vamepumesubobisatite.pdfIn PDF document text
    • http://polimak.pl/userfiles/file/5744762153.pdfIn PDF document text
    • http://exoticland.bg/upload/files/files/lajunobalokobewawov.pdfIn PDF document text
    • http://huanghels.com/filespath/files/20210916080610.pdfIn PDF document text
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/16134e5df73ad1---xawuruxafakivafumogol.pdfIn PDF document text
    • https://projectmine.hu/ckfinder/userfiles/files/15088790919.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/52271039408.pdfIn PDF document text
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613eb63ec6667---4941088011.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/161387e058acf3---3652533180.pdfIn PDF document text
    • http://www.alliance-bio.com/user_data/editor/ckfinder/core/connector/php/upload/files/mamidu.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/towibutilenubesusoluzizi.pdfIn PDF document text
    • https://exam10.menapoint.com/app/webroot/upload/files/rupikinunola.pdfIn PDF document text
    • https://efficimm.fr/userfiles/files/89970247658.pdfIn PDF document text
    • http://phunggia.biz/userfiles/file/noruxe.pdfIn PDF document text
    • http://beloezoloto.ru/userfiles/file/dimafonetusal.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=status+bar+ios+apkPDF 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_off0000cbcc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBCC 17540 bytes
SHA-256: a67097fe3c2aaf4657d0580e5b195870c445cca9f1a17794c7afde03005f0134
font_01_sfnt_off0000f97b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF97B 10368 bytes
SHA-256: 1f2f33943aad6016c03093a204ee0f2f996c439e67ee6e191abca412665929d9
font_02_sfnt_off000110d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110D3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1