Malicious PDF — malware analysis report

Static analysis result for SHA-256 6d88f57de2d05c49…

MALICIOUS

PDF

85.1 KB Created: 2021-09-17 13:45:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: eebbc5382584ee9973db994537b82289 SHA-1: 94c2cb4d8fa8c51ee5c3195cbf2646eee5d40017 SHA-256: 6d88f57de2d05c49ad3db28d2d806f754418500b6cdccd3bf8ca27fe83766e01
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 it functions as a link farm, with many embedded URLs pointing to various websites, including some hosted on compromised WordPress installations. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/bukixinodesa.pdf In PDF document text
    • https://bosingels.nl/ckfinder/userfiles/files/8134729571.pdfIn PDF document text
    • http://kenzoum.org/home/integrity/public_html/ckfinder/userfiles/files/rudajegovasakupuv.pdfIn PDF document text
    • https://isagrinio.gr/userfiles/xagiwafarumabu.pdfIn PDF document text
    • https://sabunwangi.com/contents/files/48243238136.pdfIn PDF document text
    • http://classicalgardenstatues.com/uplds/file/mudazivalonapiworen.pdfIn PDF document text
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/9ab9e03e8cd6a5b8b7f67d7d3e8b4345/77974688101.pdfIn PDF document text
    • http://lighthouse-connection.at/myPix/file/vatumivofamumixafono.pdfIn PDF document text
    • http://muszempilla.com/files/file/62518858981.pdfIn PDF document text
    • https://quatcongnghieput.com/uploads/files/94433755985.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/kupowutodaziwamel.pdfIn PDF document text
    • https://virtrade.gr/userfiles_lybo/file/jomipivimovadivogip.pdfIn PDF document text
    • https://www.myjamaicais.com/wp-content/plugins/super-forms/uploads/php/files/dc66de708e23304b65a6b590b9214093/jukovado.pdfIn PDF document text
    • http://duoctruongxuan.vn/userfiles/image/file/josogef.pdfIn PDF document text
    • https://www.kuwaitpolyurethane.com/ckfinder/userfiles/files/folefomazomo.pdfIn PDF document text
    • https://tw-itemaos.com/ckfinder/userfiles/files/37435692031.pdfIn PDF document text
    • https://festivalecolo.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613d119f58def---xulefufotusafa.pdfIn PDF document text
    • https://sicurezzaips.it/uploads/file/34296806083.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142e3978a741---85262565264.pdfIn PDF document text
    • http://henca.com/files/details/file/jitodopusixi.pdfIn PDF document text
    • http://thietbikhachsanvinhhung1.com/upload/files/50107369434.pdfIn PDF document text
    • https://huuphongplastic.vn/uploads/images/files/23475496477.pdfIn PDF document text
    • https://aradmissions.com/ci/userfiles/files/tusegizirutakofexar.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=android+screen+video+recording+appPDF 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_off0000e7ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7FF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010011.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10011 18056 bytes
SHA-256: 757ffbfbb16e9c0001dcf1db16abde8ad43230eac78ef905673bc08e283b42c8
font_02_sfnt_off00012e6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E6A 10592 bytes
SHA-256: 822d9aad20893b83e25e8f23020b836cacbefa41fcd48a110f3361e44337269f