Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa40bc7b8bee4e12…

MALICIOUS

PDF

88.7 KB Created: 2021-08-14 12:00:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 5d7cf3e9ccd986efe535cd1bb940df0d SHA-1: 8c1ce69ec26ca1f5df0f0836c068c4a469c04dfc SHA-256: aa40bc7b8bee4e12d5515adae44ab474330996c7aadec035c7731c9390ba7e87
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Several heuristics indicate the PDF contains a link farm pointing to compromised WordPress upload storage, suggesting an attempt to distribute malicious content or phish users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct textual clues to the attack's intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

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://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1607a33501550d---bebagidarimoxiberopun.pdf In PDF document text
    • https://prcomponents.com/ckfinder/userfiles/files/31578032821.pdfIn PDF document text
    • http://hoteldazegliotorino.com/userfiles/files/34363759837.pdfIn PDF document text
    • https://amitadevnani.com/userfiles/file/lejaduv.pdfIn PDF document text
    • https://okud-istra.hr/userfiles/file/topagujowegerawotupik.pdfIn PDF document text
    • https://nepalihemp.com/ckfinder/userfiles/files/wufakub.pdfIn PDF document text
    • http://circuitvietnamcambodge.com/hinhanh/file/betokedetisizuliju.pdfIn PDF document text
    • http://kirakuramenandsushi.com/uploads/files/64464067799.pdfIn PDF document text
    • http://interel-rus.ru/test/sites/default/files/file/fegakebixifebapuxuj.pdfIn PDF document text
    • https://printjet.pl/pliki_user/File/11653162028.pdfIn PDF document text
    • https://istanajp2.com/contents//files/82764773621.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1cfdfb19ce---50837959332.pdfIn PDF document text
    • https://cursosadistanciayonline.com/medios//files/38996230450.pdfIn PDF document text
    • http://maroba-zirndorf.de/file/87101324736.pdfIn PDF document text
    • http://www.accessibilite-salle-eau.com/ckfinder/userfiles/files/26628062166.pdfIn PDF document text
    • http://www.asejnrtigers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16097c422dc058---23584009344.pdfIn PDF document text
    • http://interface-referencement.com/userfiles/file/tolafusibiwux.pdfIn PDF document text
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/ca29e6acddc336019f37f38a16cfd4c6/49474571253.pdfIn PDF document text
    • http://neodev.space/wp-content/plugins/formcraft/file-upload/server/content/files/1609f40266c7d6---52069394060.pdfIn PDF document text
    • https://beribuket.ru/wp-content/plugins/super-forms/uploads/php/files/75346cc24a562abdeebd28a4debeef18/dowizutom.pdfIn PDF document text
    • http://itnetworkconsultingsf.com/helpdesk/app/webroot/img/userfiles/files/34356755866.pdfIn PDF document text
    • https://coevent.ru/upload/files/gifabonivip.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=licencia+para+eset+nod32+actualizado+hasta+el+2022PDF 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_off0000f3a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3A7 11140 bytes
SHA-256: 3fcf39d1564e259f82f1f381fa2ebe6e5435f2c007cf731bf8cc77fdc4f74f2f
font_01_sfnt_off00010dae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DAE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000125c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125C0 17832 bytes
SHA-256: 169dc716cf46bef658ac28bd959b61ab80095dc7b76e5cd31538708361402ded