Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d5a13ae6bea2e43…

MALICIOUS

PDF

80.2 KB Created: 2021-10-09 05:11:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: cb94793aceaa21aab88ec8af6ea49650 SHA-1: 6768559d3f22a5768b92e02d23dc269030302cbc SHA-256: 4d5a13ae6bea2e435c22108e19879c08dba13b42d750d347861850a96356a388
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised WordPress upload directories or disposable hosting, suggesting a link farm designed to redirect users. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create PDF documents from web content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://solener.info/ckfinder/userfiles/files/21139972304.pdf In PDF document text
    • http://saigonford3s.com/uploads/2021-09-24/images/files/27124084128.pdfIn PDF document text
    • http://traslochimontalto.it/userfiles/files/diwigamedolazu.pdfIn PDF document text
    • https://grandegroup.net/files/varunomuxumefuwikanalunu.pdfIn PDF document text
    • http://hajnysport.cz/FCK_userfiles/file/vunifurel.pdfIn PDF document text
    • http://nomorecpapmachine.com/userfiles/files/pogiwebiwejifunonuwu.pdfIn PDF document text
    • http://phutungototuanphat.com/img-tvdl/files/lovibonafolen.pdfIn PDF document text
    • http://dekobonner.de/userfiles/file/73666486035.pdfIn PDF document text
    • http://maksimetall.ru/files/60042137007.pdfIn PDF document text
    • https://xn--p3t29jo1ed4o4xw.tw/upload/files/kaxuxukiniruvapudiburulaz.pdfIn PDF document text
    • https://christianklein.eu/Quansis/ckfinder/userfiles/files/muzexosifanev.pdfIn PDF document text
    • http://www.goataxiservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/161589ef526084---14805048537.pdfIn PDF document text
    • http://pate4me.com/userfiles/file/nilapokupijilijigaraxo.pdfIn PDF document text
    • https://rotitelor.com/contents/files/2696809031.pdfIn PDF document text
    • http://www.fullmooneye.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614663be81c92---72356053173.pdfIn PDF document text
    • http://sensitiva.fi/UserFiles/File/xokigoxarivu.pdfIn PDF document text
    • http://les-dvorik.ru/userfiles/file/vukememogi.pdfIn PDF document text
    • https://lekkermooi.nl/userfiles/file/71260262455.pdfIn PDF document text
    • http://biolabsrl.org/userfiles/files/60900705801.pdfIn PDF document text
    • https://adproissy.emailingmanager.com/uploads/editor/file/29198441768.pdfIn PDF document text
    • https://www.sophrologue-nimes.fr/upload/news/files/vifibi.pdfIn PDF document text
    • http://novehorizonty.sk/userfiles/file/37795844306.pdfIn PDF document text
    • http://gurolmumcu.com/userfiles/file/74724914331.pdfIn PDF document text
    • https://sodigital.it/wp-content/plugins/formcraft/file-upload/server/content/files/16143c1563df6f---lasilawawar.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=general+questions+for+interview+and+answers+for+a+fresherPDF 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_off0000d528.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD528 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ed3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED3A 17516 bytes
SHA-256: bc99fa4b7b7a19637590a02d845bf12a1758d2bda43ded536ee9f09bbafca159
font_02_sfnt_off000119b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119B2 10888 bytes
SHA-256: 653375b091150d89abb32eb471a42ccd104eab3b0b47344cdafeefff7c5fd1b4