Malicious PDF — malware analysis report

Static analysis result for SHA-256 432dc3c19c6db85b…

MALICIOUS

PDF

81.9 KB Created: 2021-09-11 02:46:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d79db74125441cb4bf60df3cebad47c2 SHA-1: 07455a7f2076b8724e0b422c379c01ed46de3328 SHA-256: 432dc3c19c6db85b9aab65cf99250ef675b641ac8428c06b46f5c945ae7d4327
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with high-severity heuristics indicating it's a link farm on disposable hosting and contains algorithmically generated URLs. The PDF structure and numerous external links suggest a phishing or malware distribution attempt, likely using spearphishing as an initial access vector. No scripts were extracted, but the overall pattern points to a malicious document designed to redirect users to potentially harmful sites.

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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=desi+esp+non+root+apk PDF link annotation
    • https://larrialdiak.es/files/galeria/files/luzopozebibiwopadoboves.pdfIn PDF document text
    • http://fruhmann-elektrotechnik.at/28686844274.pdfIn PDF document text
    • https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132b16d42bf9---jewowetozekezokawipinobaf.pdfIn PDF document text
    • http://phamtrangia.site/upload/files/84780270019.pdfIn PDF document text
    • https://perfecthospital.org/FCKeditor/file/4264985046.pdfIn PDF document text
    • http://youngdongtec.com/userfiles/file/xezuporasiga.pdfIn PDF document text
    • https://posaonakosovu.com/ckfinder/userfiles/files/29981600522.pdfIn PDF document text
    • https://lecormier-menuiserie.com/www/upload/files/sofutosuran.pdfIn PDF document text
    • http://ssteelelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/90635545179.pdfIn PDF document text
    • https://superiorservicesandsolutionsfl.com/nbloom/fckuploads/file/16710110625.pdfIn PDF document text
    • https://lawweb.info/mycms/admin/userfiles/file/38573381431.pdfIn PDF document text
    • https://neksav.com/upload/ckfinder/files/96986684555.pdfIn PDF document text
    • http://bakefruit.com/uploads/files/202109091316445697.pdfIn PDF document text
    • http://vinacafe-dalat.com/Images_upload/files/1038600851.pdfIn PDF document text
    • http://letnipohar.cz/upload/file/kelutasefozasiguzupab.pdfIn PDF document text
    • http://rudolphalexander.com/uploads/files/26880849967.pdfIn PDF document text
    • https://academiapreprod.riportico.com/userfiles/files/dolonox.pdfIn PDF document text
    • https://heritran.vn/uploads/news_file/8723925547.pdfIn PDF document text
    • https://shunnasato.com/14097604983.pdfIn PDF document text
    • http://novaserv.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137fb19318a7---tuvuxupununusapumuka.pdfIn PDF document text
    • http://yokohama-model.com/userfiles/files/rejidi.pdfIn PDF document text
    • https://suprizpin.com/calisma2/files/uploads/zepaxurazorifipoz.pdfIn PDF document text
    • https://bestcaps99.com/ckfinder/userfiles/files/68584923699.pdfIn PDF document text
    • https://watertorens.nl/userfiles/file/39952292676.pdfIn PDF document text
    • http://artio.pl/files/files/nededexul.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_off0000daa5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAA5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f2bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2BC 10292 bytes
SHA-256: 071cbe3085e42ea8359ded741cc3c181273616cd7036b7c1c509b0cb757ec0ea
font_02_sfnt_off00010a14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A14 18484 bytes
SHA-256: d5af716e3738d39b79efbfbd07e647c28a4a6aa070789788f7a989fd6cee6bad