Malicious PDF — malware analysis report

Static analysis result for SHA-256 89275dc8771fb239…

MALICIOUS

PDF

88.8 KB Created: 2021-09-19 14:32:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 55a4050d618a7910d66e1af5140ffe3e SHA-1: 076374c387de4822f2b0657975d226253eb83aef SHA-256: 89275dc8771fb239812fb088b5aaa5ca87678a6314728e068e719be73abc4685
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified the PDF as a link farm, with many links pointing to potentially compromised WordPress upload directories and disposable hosting. 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 0.9942

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 http://tmkb.org.tr/ckfinder/userfiles/files/5719819515.pdf In PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161427ce2e261b---rewipekuwuvamutipagew.pdfIn PDF document text
    • https://sitycare.com/FCK-UserFiles/files/diwole.pdfIn PDF document text
    • https://hotararicedo.ro/files/files/73725169632.pdfIn PDF document text
    • http://mdknoodles.co/uploads/files/masidepokupokiwopubedo.pdfIn PDF document text
    • https://bnovum.hu/downloads/35218656164.pdfIn PDF document text
    • http://crmrealty360degree.in/userfiles/file/newitelefijinivawurawivul.pdfIn PDF document text
    • https://mi-stores.com/basketballtotaal/images/editor/file/65973769123.pdfIn PDF document text
    • https://careersourcechipola.com/files/public/58208890556.pdfIn PDF document text
    • http://cpbnatation.fr/fckeditor/userfiles/file/fegudepekezubogi.pdfIn PDF document text
    • http://www.marcado.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16140d61f7a047---poluganulogaroj.pdfIn PDF document text
    • http://mazdooradda.com/userfiles/file/38128472424.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/161306586e6fae---zejabigifowapami.pdfIn PDF document text
    • http://anpo.vn/upload/files/ximozodinetidugexa.pdfIn PDF document text
    • http://totaleclipsenv.com/wp-content/plugins/formcraft/file-upload/server/content/files/161372d5ac0515---46802420553.pdfIn PDF document text
    • http://kietminhrivet.com/upload/files/bijixikifo.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/16136129519f76---11610124041.pdfIn PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/16135c4a344ccd---wojepuzus.pdfIn PDF document text
    • https://motelandratecuci.ro/userfiles/file/23672356653.pdfIn PDF document text
    • http://solyaris.pro/admin/ckfinder/userfiles/files/jerajuz.pdfIn PDF document text
    • http://risme.vn/files/bulugaxisomukefakovu.pdfIn PDF document text
    • http://simpelms.nl/userfiles/files/mugorazulofawavel.pdfIn PDF document text
    • http://travelbilet.ru/sites/default/files/file/wopaliloju.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=huckleberry+finn+online+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://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_off0000f6ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6AE 18180 bytes
SHA-256: e1148d8371438a331a715768c4bed96f7e7292f5947f044dc5cd500edbb1d183
font_01_sfnt_off00012602.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12602 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013e19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13E19 10620 bytes
SHA-256: 3202f38c097a67ba0cbbc97fe770b7ddd4c43ae47c0c99eb9f5a57fddfb3606a