Malicious PDF — malware analysis report

Static analysis result for SHA-256 a855c6a360283d20…

MALICIOUS

PDF

79.5 KB Created: 2021-09-18 20:38:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4d096d896f89a6402902fbff7fe05738 SHA-1: 14e993625594e455b95d9bf3823dcbe13746646e SHA-256: a855c6a360283d20f79953e942e7001aea57938ad3325e5df511a673280ccde9
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised WordPress upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and appears to be junk data, providing no direct clues about the intended lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://krisoc.ru/uplcv?utm_term=amazing+spider+man+wallpaper+for+android PDF link annotation
    • https://gaziemirkentkonseyi.com/upload/files/39034769119.pdfIn PDF document text
    • https://trungtammatnamviet.vn/upload/files/82822680314.pdfIn PDF document text
    • http://eyela.kr/uploadfile/fckeditor/file/66526525593.pdfIn PDF document text
    • http://balmybnb.com/t/tutorfirm/uploads/ck/files/2142177847.pdfIn PDF document text
    • http://viprealestatebrokers.com/userfiles/files/71331225311.pdfIn PDF document text
    • http://ldkxzzs.com/images/userfiles/file/49357064325.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16134152d31187---lefakeganodokuk.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/698808761f72fe80f8f5fd6c13b3d3e0/xewukozugunonerurumovegoz.pdfIn PDF document text
    • http://ferien-in-zahren.de/images/file/48564376145.pdfIn PDF document text
    • http://globalsocialwlefaresummit.com/app/webroot/uploads/ckuploads/files/9053539130.pdfIn PDF document text
    • https://www.thecandystoresudbury.com/wp-content/plugins/super-forms/uploads/php/files/r3hgsjikkilnetog2qt1uf00ke/34497631444.pdfIn PDF document text
    • http://eros-arena.name/eros/userfiles/file/40013562657.pdfIn PDF document text
    • https://bandotrading.com/uploads/file/lunaxafewejuwiwepovexe.pdfIn PDF document text
    • https://genesisbehaviorcenter.com/wp-content/plugins/super-forms/uploads/php/files/c231f553c66f4471995bcb874343d3fd/8371071047.pdfIn PDF document text
    • http://acsalma.hu/userfiles/files/repopezotobixuxoson.pdfIn PDF document text
    • https://sklep-pinokio.pl/web/uploads/files/2410143590.pdfIn PDF document text
    • http://ultraljud.nu/bild/files/wusezepezaled.pdfIn PDF document text
    • https://magiccat.pro/ckfinder/userfiles/files/jodipagibobavivoponufin.pdfIn PDF document text
    • http://luijkzonwering.nl/image/file/2332619937.pdfIn PDF document text
    • https://naseeha.org/wp-content/plugins/super-forms/uploads/php/files/2f617cc301766f4c5c37367791077ab1/57000862432.pdfIn PDF document text
    • http://partnercable.com/files/23048395405.pdfIn PDF document text
    • http://buyyoutubesubscribers.com/ci/userfiles/files/midipojoduzotamukakugi.pdfIn PDF document text
    • http://mail.me.ntou.edu.tw/ckfinder/userfiles/files/20210908_152250.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_off0000d02d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD02D 18032 bytes
SHA-256: 7b3b11c3df888de5aba1c59bf57f1c143af1972da48a680412d6a4698f76d7db
font_01_sfnt_off0000fef2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEF2 10872 bytes
SHA-256: 8c922f25499615ec001d855fb2a546e1742c671a439c0f23b2aebe08d460f0a5
font_02_sfnt_off000117e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117E8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1