Malicious PDF — malware analysis report

Static analysis result for SHA-256 28ca7d4d1676fe1a…

MALICIOUS

PDF

80.7 KB Created: 2021-06-22 21:30:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 6870504dbd8e214c5eb1b11ba15fc5dd SHA-1: 1e29e57a68c091d48bc567eb0eb5016bfa4e51d6 SHA-256: 28ca7d4d1676fe1a706f4c5021095345e5be2c5928b9639dd9c7a10266ad4303
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains a link farm pointing to compromised WordPress upload storage, suggesting an attempt to redirect users to malicious content. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://dodici12.ru/wp-content/plugins/super-forms/uploads/php/files/9ipq8sjiful058i599bqeh2472/fimujoparade.pdf In PDF document text
    • https://www.alarisusallc.com/wp-content/plugins/super-forms/uploads/php/files/1daf2fcb64cda0f2f78776dc9b8b9976/1552879350.pdfIn PDF document text
    • https://www.entornopublicitario.com/wp-content/plugins/super-forms/uploads/php/files/5d1130c9c78fbdecdab6d09a6bc28208/muwodawunedi.pdfIn PDF document text
    • http://go-trec.com/wp-content/plugins/super-forms/uploads/php/files/7edos5694vc15n3hopi9pdpctm/kelogel.pdfIn PDF document text
    • http://penzionklara.cz/userfiles/file/bebiketifisego.pdfIn PDF document text
    • https://lashmakerpro.it/wp-content/plugins/super-forms/uploads/php/files/1i8iruo52c3vknmbbovoa370o5/gatokulurotulixeni.pdfIn PDF document text
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/8917ljoj1bs4jquju5cv2oqrh5/97266517474.pdfIn PDF document text
    • https://hashtag.school/userfiles/file/16294892427.pdfIn PDF document text
    • https://orkhaconstruction.com/wp-content/plugins/super-forms/uploads/php/files/t07h1dcag6lobffm4dpj1o5br3/50382417560.pdfIn PDF document text
    • http://staging.impactredevelopment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c430c92ae3---vomemuvu.pdfIn PDF document text
    • https://homeaestheticsllc.com/wp-content/plugins/super-forms/uploads/php/files/ea28463b983424bbc02be86d156040ed/5966254407.pdfIn PDF document text
    • https://www.mozartcantat.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609a1cd35da65---35113377659.pdfIn PDF document text
    • http://josephlillianmorrisfamily.com/clients/59960/File/zepekozokokezo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=teoria+de+la+informacion+pdfPDF 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://scripts.sil.org/OFLIn 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_off0000e805.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE805 5072 bytes
SHA-256: 29ab0a26b810aa83cd9d2716af96a2312688a50cd18bdbc46fa8e83aa794cc42
font_01_sfnt_off0000f934.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF934 12248 bytes
SHA-256: 8ad53ef86c2159f9a91515d1fbbcccc7dd9fa477e3bb4fad24f833f7eaa7d1f1
font_02_sfnt_off00012164.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12164 16036 bytes
SHA-256: 149cab45689013e99d1aa520d2e5234663aa5d8577b6aae5e423b5d60aeda4c1