Malicious PDF — malware analysis report

Static analysis result for SHA-256 a88811ef590d36fa…

MALICIOUS

PDF

71.0 KB Created: 2021-09-30 16:26:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: a5e916b63b7685a4624fb7b6c2136f1d SHA-1: 8268b9cd4c0b396b0ff8fc01d2336475bba0909a SHA-256: a88811ef590d36fa37148b90117712836d76b744a1f40bd66e0bb47dd9d4e718
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs pointing to various domains, many of which appear to be part of a link farm designed to obscure the ultimate destination. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' and the presence of URLs with 'utm_term' parameters suggest a phishing or malware distribution attempt. The ClamAV detection and ML classifier further support its malicious nature, likely as a phishing lure for downloading further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://crewmak.ru/uplcv?utm_term=du+recorder+premium+download PDF link annotation
    • http://okun.su/upload/file/68408916558.pdfIn PDF document text
    • http://sandlnae.com/data/editor/file/58899668602.pdfIn PDF document text
    • http://kleinschaden.expert/userfiles/file/82447084866.pdfIn PDF document text
    • http://xfswchem.com/upload/files/xemesada.pdfIn PDF document text
    • https://www.willmarshelter.com/ckfinder/userfiles/files/kelew.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16132610eba4c4---zifetagisoro.pdfIn PDF document text
    • https://duvanco.be/docs/files/rufivobabesujimuzemone.pdfIn PDF document text
    • http://sanarina.de/ckfinder/userfiles/files/muzefosazoveruwipetin.pdfIn PDF document text
    • https://sua.vn/uploads/userfiles/file/20711282170.pdfIn PDF document text
    • http://teormech.ru/teormech/usrimg/file/98687227189.pdfIn PDF document text
    • http://www.radanhorse.com/resource/files/34466920468.pdfIn PDF document text
    • http://medicare-darmstadt.de/bilder/UserImages/file/4580115760.pdfIn PDF document text
    • http://www.rafaellucenaehijos.com/ckfinder/userfiles/files/97930062856.pdfIn PDF document text
    • http://er-trans.com/img/produkty/files/23239899955.pdfIn PDF document text
    • http://bong-dem-long.org/upload/editor/files/20061003159.pdfIn PDF document text
    • https://jphotographyllc.com/userfiles/file/pesafas.pdfIn PDF document text
    • https://gimenezricarte-deltabogados.com/ckfinder/userfiles/files/rakutad.pdfIn PDF document text
    • https://adamslakeband.org/userfiles/file/vutozovijonekiso.pdfIn PDF document text
    • http://xedaptheduc.net/app/webroot/uploads/files/35754946448.pdfIn PDF document text
    • https://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/1614f57c5ea74d---munajipimivunekugo.pdfIn PDF document text
    • https://mithermomix.com.mx/wp-content/plugins/super-forms/uploads/php/files/f7d8900059c6f5372c7d363bbabc0f93/vuvumasavasagasipafunuvi.pdfIn PDF document text
    • https://www.birdandwildlifeteam.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139b1a67d9fb---metevelogazux.pdfIn PDF document text
    • http://thy-environment.com/userfiles/files/xufubipijisevog.pdfIn PDF document text
    • http://owop.challengersports.com/ckfinder/userfiles/files/72351123026.pdfIn PDF document text
    • http://chinazzjx.com/d/files/27992945555.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_off0000b4e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB4E3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ccf5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCF5 16256 bytes
SHA-256: 618c66d134bcd8086e2c7cf06c256556692c70c14340e7df9b7b053150ca30a4
font_02_sfnt_off0000f5f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5F3 10596 bytes
SHA-256: 1f213c68293d2ae8f8180e1371a64e097116c70cf6b33e5e82f9fe50b24e6ba3