Malicious PDF — malware analysis report

Static analysis result for SHA-256 41c3843cf8bd2e36…

MALICIOUS

PDF

88.1 KB Created: 2021-07-14 09:44:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 031defff13bb388329b0ca01ac1e2379 SHA-1: 4a1ea59fb841da86414913e4590b8a129476a319 SHA-256: 41c3843cf8bd2e368deee019939ab73b2203367340d4fe52459839ac5e54ce07
156 Risk Score

Malware Insights

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

This PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of links, many pointing to compromised WordPress upload directories and disposable hosting, suggesting it functions as a link farm to distribute malicious content or phish for credentials. The document body is heavily obfuscated and unreadable, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://wasserburg.pl/userfiles/file/sulamuboxirenu.pdf In PDF document text
    • https://tripleccompanies.com/wp-content/plugins/super-forms/uploads/php/files/203efd7cac6b12b50c19166ce141d1f7/xotufosigibakofizutuz.pdfIn PDF document text
    • http://medicamarsala.it/userfiles/files/majisomezire.pdfIn PDF document text
    • https://noukos.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160bc75ea6e00c---wafesefewesolalex.pdfIn PDF document text
    • http://www.kliningstroy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608035a6e2376---50660570934.pdfIn PDF document text
    • https://xn--z4qq44i.tw/upload/actfiles/22764407506.pdfIn PDF document text
    • http://wsm.hk/images/uploadfiles/file/tuginaresofademakipipagi.pdfIn PDF document text
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c7325e2376---kanupiripepenupewebi.pdfIn PDF document text
    • http://thedewakohchang.com/image/upload/File/osexo.pdfIn PDF document text
    • https://www.arc-welding.co.uk/wp-content/plugins/super-forms/uploads/php/files/mcuuo9e5t40imqbi1vrlpoj9g3/54618482318.pdfIn PDF document text
    • http://pvsystexperts.com/wp-content/plugins/super-forms/uploads/php/files/5gu2532kaarq206cd9q6m07gi6/tiwurijodugenagifefo.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/4e9c4415d164e735cc91410e5b1ea45b/waxofonik.pdfIn PDF document text
    • https://artsketch.ru/wp-content/plugins/super-forms/uploads/php/files/9d18189bb429cdd502accec54cbd2aea/63871782087.pdfIn PDF document text
    • http://zawayakw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a491d9500db---60074125231.pdfIn PDF document text
    • https://antoinepanau.com/wp-content/plugins/super-forms/uploads/php/files/8a8173cfadb209bea2f43b84c3e7dba3/boxinasuxomabuvun.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/160982b01d37cd---kuxelewakuxobi.pdfIn PDF document text
    • http://www.morenoroofing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073fa85a2e2d---78848769481.pdfIn PDF document text
    • https://profbuhotchet.ru/wp-content/plugins/super-forms/uploads/php/files/e330a76c7987c3b05f421318601ab9e5/gujora.pdfIn PDF document text
    • https://www.kalirich.com/wp-content/plugins/super-forms/uploads/php/files/7ljh6c59f05bu5mca8odums486/60921045339.pdfIn PDF document text
    • https://biothiennam.com/media/ftp/file/ponirakaborur.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=5+minute+appetizersPDF 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_off0000f253.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF253 18632 bytes
SHA-256: c840babf632b31ca0114053fdcc3718a3f460b9a24560bf194bd30ad6ade3cd3
font_01_sfnt_off00012251.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12251 10444 bytes
SHA-256: dbb93931279bfc6b4b55f242f193af3fee45725cbe0c0e0a3586f65900f6c175
font_02_sfnt_off00013a02.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A02 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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