Malicious PDF — malware analysis report

Static analysis result for SHA-256 23ce78f516bf8d9e…

MALICIOUS

PDF

74.7 KB Created: 2021-09-07 13:09:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 4fb13855b08a2f121c284a7062d6cd77 SHA-1: 5abff1ca808e18ee134d780772fb3a0b375f2fb7 SHA-256: 23ce78f516bf8d9ee1dd934350b1a1051c3539d6a5a84587d6277c527a87a196
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by a machine learning classifier and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, containing numerous URLs pointing to compromised CMS uploads and disposable hosting, likely intended to redirect users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://digireg.pl/upload/45989811291.pdf In PDF document text
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/160e82af62855d---sazikoziziwumubodejejojuw.pdfIn PDF document text
    • http://bagiez.de/userfiles/file/vasibisa.pdfIn PDF document text
    • https://postscriptproductions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609400bd96fa8---duwinawul.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/jjf95tbugjj0mo029qeugss5o4/nujabesi.pdfIn PDF document text
    • https://christembassybarking.org/wp-content/plugins/super-forms/uploads/php/files/d42137a9b04a86608cda81030c3c1f08/49266587744.pdfIn PDF document text
    • http://jilienjrubin.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/88481821846.pdfIn PDF document text
    • https://alarrabnews.com/images/content/content/file/18825948521.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b1017db26b9---70247859478.pdfIn PDF document text
    • https://www.formwork.co.uk/wp-content/plugins/super-forms/uploads/php/files/7o814v6vlu6t9pctcnd16csiqu/zoronomafatad.pdfIn PDF document text
    • http://safeabortionnepal.com/userfiles/file/wemosufu.pdfIn PDF document text
    • http://zaun-produzent.de/userfiles/file/27346441070.pdfIn PDF document text
    • https://notofthisgalaxy.com/wp-content/plugins/super-forms/uploads/php/files/k1k2k2n4fqpkdre1e3jvjrg0pi/wowikejokolof.pdfIn PDF document text
    • http://metalltechnik-kutschi.at/vovufofizunorifeditup.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/1f65819b3c17dc205c9a5de4e59d29d2/38044843276.pdfIn PDF document text
    • https://rmissio.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160c531c016e47---18198001006.pdfIn PDF document text
    • https://readxyz.com/wp-content/plugins/super-forms/uploads/php/files/35446cfe073cc19b60fe5fa2d4c38dfc/51669922273.pdfIn PDF document text
    • http://veiligheidsslot.nl/ckfinder/userfiles/files/jixusinorevuvaw.pdfIn PDF document text
    • https://bangvetthuong.com/luutru/files/visujesot.pdfIn PDF document text
    • http://medicare-darmstadt.de/bilder/UserImages/file/73920179396.pdfIn PDF document text
    • https://www.xyoaa.org/sites/default/files/files/8185470942.pdfIn PDF document text
    • http://eichler-kammerer.de/34466251765.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=drawing+techniques+pdf+downloadPDF 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_off0000bdcd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDCD 11232 bytes
SHA-256: 540f2af2e2b6dea44026314027a91a0350b8dbf6d65df3ae6d4bd6631e043329
font_01_sfnt_off0000d79a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD79A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000efac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFAC 17664 bytes
SHA-256: 2e80af8f69967aa7774405a0a96746857a2b560ceb56154f950684b16bd21623

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