Malicious PDF — malware analysis report

Static analysis result for SHA-256 f7561ab550614596…

MALICIOUS

PDF

83.0 KB Created: 2021-09-03 08:11:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 03334f175cdc80e08c9eae3623e3e195 SHA-1: 4db5b821daf9ecc156d67664b72a4be232415cb5 SHA-256: f7561ab55061459657754ea742bfbb1ac384e45ffbaf8653816e3e07057d3ec9
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and an ML classifier as malicious, with ClamAV detecting it as a phishing trojan. It contains numerous embedded URLs that form a link farm, directing users to potentially compromised websites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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://krisoc.ru/uplcv?utm_term=nursing+care+plan+for+kidney+disease+pdf PDF link annotation
    • http://phrabat.net/UserFiles/File/zeguraneluberifevez.pdfIn PDF document text
    • https://www.asahinadigital.com/wp-content/plugins/super-forms/uploads/php/files/mrm1cuun692tbs680d5tf3r7a4/vobixeboletozijotuwivez.pdfIn PDF document text
    • https://www.rosebankprimary.co.za/inc/ckfinder/userfiles/files/48285714495.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f0756bd059---juwunedu.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/160c9ffbd48e1d---90784110595.pdfIn PDF document text
    • https://deedpoll.sg/wp-content/plugins/super-forms/uploads/php/files/9ed02453fff884f6e7201f48f6c7228e/nukumasogudelumisafe.pdfIn PDF document text
    • http://alexhofford.com/temp/files/file/gisavigag.pdfIn PDF document text
    • https://zazilha.com.mx/wp-content/plugins/super-forms/uploads/php/files/fba0e21230f9167c0406081d46d6cbc0/83104143724.pdfIn PDF document text
    • https://sportli.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/16099a3cfb0af6---63564831292.pdfIn PDF document text
    • http://tovicetour.com/FileData/ckfinder/files/20210626_9F66E258E54A59DD.pdfIn PDF document text
    • http://rheumatology.institute/upload/content/file/84824936191.pdfIn PDF document text
    • http://nousgarage.com/userfiles/file/vunojamovuguxami.pdfIn PDF document text
    • https://bakwanudang.com/contents//files/80375774453.pdfIn PDF document text
    • http://maybomchuachay24h.com/Images_upload/files/9639543055.pdfIn PDF document text
    • https://creationstationdance.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089690c624b6---16842141467.pdfIn PDF document text
    • http://www.benvenutialmare.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f1a729fe67---13292687025.pdfIn PDF document text
    • http://duythuc-bearing.vn/uploads/userfiles/file/majikigibanoxaxotob.pdfIn PDF document text
    • https://sudhirsachdevaclasses.com/ci/userfiles/files/lupoxisutovokodelamox.pdfIn PDF document text
    • http://ukrainski-rosyjski.pl/userfiles/file/gewibowevetarevov.pdfIn PDF document text
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/3e134945a5a661327e2e14c7417b5e63/sovidamit.pdfIn PDF document text
    • https://blindnow.com/userfiles/file/11747716143.pdfIn PDF document text
    • http://aldo-ins.com/userfiles/file/balusipa.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/u1ajvvkhsf1hmmeh2i6tvllta6/pefanetikututa.pdfIn PDF document text
    • https://www.blackandwhite-salon.com/wp-content/plugins/super-forms/uploads/php/files/tmp/25039137206.pdfIn PDF document text
    • http://maxbrio.kr/files/files/19372104373.pdfIn PDF document text
    • https://www.proctoloji.com/wp-content/plugins/formcraft/file-upload/server/content/files/160704871d1346---zukumebigifo.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_off0000e0a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0A0 10980 bytes
SHA-256: 098f149e7b689d46e38cbf8d5a056d5249910add6cc3e9c98a5dc842aa620b8d
font_01_sfnt_off0000f9ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9FF 16876 bytes
SHA-256: b32ee0c448ce1acbbe85f05206ebb9ae2b00aa882a6a48457a8e42d603940593
font_02_sfnt_off0001258e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1258E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1