Malicious PDF — malware analysis report

Static analysis result for SHA-256 c557a31df81d0e38…

MALICIOUS

PDF

87.0 KB Created: 2021-07-18 07:37:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: f41ad6b1def51d3d684450c1a9694cfd SHA-1: dc85eddde68f094412fd4fdd69991e8b7c3123a3 SHA-256: c557a31df81d0e385e5ee97688e0f89770b620383bcce4faf4323880250464e6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, indicating a link farm for phishing or malware distribution. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were explicitly extracted, the PDF structure and embedded URLs point towards a malicious document designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://noticky.net/akce/fotky/file/99755270217.pdf In PDF document text
    • http://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160957443d419b---zuteravuzapikosavatunubo.pdfIn PDF document text
    • http://bertoniamministrazione.it/bertoni/public/file/zukawusib.pdfIn PDF document text
    • https://autoandtruckrepair.net/nbloom/fckuploads/file/23977569029.pdfIn PDF document text
    • https://budapestpainter.hu/ckfinder/userfiles/files/repasemaxivawokozujodefup.pdfIn PDF document text
    • http://bkht.vn/userfiles/file/bujederazejuxep.pdfIn PDF document text
    • http://hurtowniagrafit.pl/userfiles/file/74694965103.pdfIn PDF document text
    • http://leadershipcareer.kr/fckeditor/_upload/file/safavuxoputafujo.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a961b9e36d7---luxobexok.pdfIn PDF document text
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/kuaodbf104ta3nj2bvrbus3o04/88288407648.pdfIn PDF document text
    • http://www.nisbd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609dce7378c66---zukavolanofosorikumubazi.pdfIn PDF document text
    • http://fygl.net/uploads/file/180843595696.pdfIn PDF document text
    • http://evabody.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160aa7510ecd95---tijodefepabiv.pdfIn PDF document text
    • https://happycustomerservice.com/wp-content/plugins/super-forms/uploads/php/files/ede8aba01d7b96f7fc2740ce3dbb8cf2/kilodogirinavana.pdfIn PDF document text
    • https://dsodrecital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8743d6d86---88518694561.pdfIn PDF document text
    • https://lerong.vn/wp-content/plugins/super-forms/uploads/php/files/ce1c8e03742f351249223c03d8c6af07/pezezipoxipitoge.pdfIn PDF document text
    • http://n2nlah.org/UserFiles/file/janaxinapa.pdfIn PDF document text
    • https://bjjewels.net/nbloom/fckuploads/file/botoxepikej.pdfIn PDF document text
    • http://pcmcpropertyblog.com/wp-content/plugins/super-forms/uploads/php/files/191afc28400021460044d380f611c214/wukorigofajufutizip.pdfIn PDF document text
    • http://www.psstrecno.sk/wp-content/plugins/formcraft/file-upload/server/content/files/160769c103534d---pakunozabi.pdfIn PDF document text
    • https://webtraffic.ch/wp-content/plugins/super-forms/uploads/php/files/lucs626h7ednv9jg710hfgdvg2/gibofiguremidusijurezad.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/8034238928c7f284034228478421b85f/vokiwofibanidazibek.pdfIn PDF document text
    • http://allprintusa.com/admin/images/file/4433092206.pdfIn PDF document text
    • http://solamsys.com/userData/board/file/gewilikoza.pdfIn PDF document text
    • https://hinodanang.com/uploads/image/files/81519233273.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=software+convert+pdf+to+pptPDF 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_off0000f094.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF094 16900 bytes
SHA-256: eebfb0bf08da807bdcfb24e8974ee2ca9d614219cf6252854dbd04cd1231a8a7
font_01_sfnt_off00011ce0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CE0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000134f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x134F7 10532 bytes
SHA-256: 018da60980ea451f0e2b2424873805cb5d48423b66f3f97efaf3428de80276b1