Malicious PDF — malware analysis report

Static analysis result for SHA-256 137dfbc33901cb73…

MALICIOUS

PDF

91.0 KB Created: 2021-09-10 15:25:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 2570b2e94e3f4ce23f2d0652c1c793bf SHA-1: 5c2703319dede90bf3a60f05a9039607e336fa29 SHA-256: 137dfbc33901cb737b7ab499912e651b401ae0a656d38ce0cc3417b9d495cf3b
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the document functions as a link farm, directing users to multiple potentially compromised websites. The presence of numerous unknown URLs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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 http://remobudostol.pl/pliki/ginejofakiw.pdf In PDF document text
    • http://studiobaliva.eu/userfiles/files/39309228584.pdfIn PDF document text
    • http://studiosiciliani.eu/userfiles/files/bimawuzeginivabikasepafar.pdfIn PDF document text
    • http://czdashan.cn/uploadfile/file/2021090501464673499.pdfIn PDF document text
    • http://bronnicy.inhome360.ru/admin/ckfinder/userfiles/files/48776148725.pdfIn PDF document text
    • http://alsace.annuaire-regional.com/ckfinder/userfiles/files/1421089970.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/161315ab88f4f4---dewivodedor.pdfIn PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/1613520faeb90b---22940608770.pdfIn PDF document text
    • http://polletnv.be/uploads/files/kogugeg.pdfIn PDF document text
    • https://etonbio.com/newsLetters/images/file/22010865801.pdfIn PDF document text
    • http://topenglish.sk/app/webroot/gallery/files/23581179767.pdfIn PDF document text
    • https://volandovia.it/public/fileeditor/file/36874399172.pdfIn PDF document text
    • https://bishopsalamatkhokhar.org/userfiles/file/84254031164.pdfIn PDF document text
    • http://vertracapital.com/uploads/files/90630931601.pdfIn PDF document text
    • https://noithatkuongthinh.com/uploads/files/5530968528.pdfIn PDF document text
    • http://envigest.cz/upload/file/xawon.pdfIn PDF document text
    • http://rsti.biz/files/fck/file/nugozenifaledogirivufu.pdfIn PDF document text
    • http://geredekombiservisi.com/userfiles/file/tomakovetime.pdfIn PDF document text
    • https://domilot.com/uploader/files/10456067387.pdfIn PDF document text
    • http://k-yoga.org/file_upload/spaw_upload/file/20210906061548.pdfIn PDF document text
    • http://sampoernastrategic.com/uploads/image/files/damonebemawisinefono.pdfIn PDF document text
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/iod15r8eimmg6v651o4oc5f6tn/nesixiwunino.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=dragon+quest+monsters+androidPDF 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_off0000f2a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2A4 22768 bytes
SHA-256: 575e1a6e5bcd84b7f845ae868fcaac15bb780756f100e5b8dfa15d970d97d024
font_01_sfnt_off00012e56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E56 10792 bytes
SHA-256: 4343fe1a70fd560356286bc71e7278fa2e15eab7fd6b068a0ce3ba31c406530b
font_02_sfnt_off000146af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x146AF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1