Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f1c63ba241e993…

MALICIOUS

PDF

81.0 KB Created: 2021-09-23 18:14:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 0cfb49cc64420c7f69719ab403c98822 SHA-1: 1e734e64b29cb25022bd55c99629334f4a712f42 SHA-256: 81f1c63ba241e993c873fef8696d20f5c6a4773e2a721ece9ce43af04c2fc0fd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to potentially compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and heuristic firings point towards an attack pattern involving redirection to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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://infrive.ru/uplcv?utm_term=snake+eyes+2021 PDF link annotation
    • http://msdoubrava.cz/foto/images/file/luput.pdfIn PDF document text
    • https://tabularasa.lv/sites/tabularasa/uploads/documents/files/54696511975.pdfIn PDF document text
    • http://open.ua/uploads/ckeditor/files/megisujepoxexo.pdfIn PDF document text
    • http://foto-recepty.sk/images/fotky/foxukowunevepokezupofe.pdfIn PDF document text
    • http://synergyproperty.com/images/files/kitun.pdfIn PDF document text
    • http://generoussecurity.com/uploads/sevebipupiwa.pdfIn PDF document text
    • https://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/b0b126ed83a5c3555c7730e87fb4b752/defir.pdfIn PDF document text
    • http://www.sport-konyv.hu/userfiles/file/87081966002.pdfIn PDF document text
    • https://www.harnoordesigns.com/wp-content/plugins/super-forms/uploads/php/files/8948aa53eb04817d87746ebfbab9d95e/xibeletawerexisiragibok.pdfIn PDF document text
    • http://xn--b1afklwjc5g.xn--p1ai/ckfinder/userfiles/files/vefukuguzideviliwiwete.pdfIn PDF document text
    • http://banglenhospital.com/UserFiles/File/diwekidifabivobep.pdfIn PDF document text
    • http://robvancampen.nl/userfiles/file/40286630665.pdfIn PDF document text
    • http://wangyiphk.com/userfiles/71087243911.pdfIn PDF document text
    • https://lingchuanfloor.com/app/webroot/userfiles/files/kojazobijokozagadimulolew.pdfIn PDF document text
    • http://sva-jeanroze.com/xmedia/file/83356168402.pdfIn PDF document text
    • http://hyundaihungthinh.com/uploads/images/files/13983032782.pdfIn PDF document text
    • http://lideparts.com/userfiles/file/1631771354.pdfIn PDF document text
    • http://baldonimarcostudio.eu/userfiles/files/50368311881.pdfIn PDF document text
    • http://co-mit.com/uploads/files/zeredavuka.pdfIn PDF document text
    • http://targhevaticane.it/userfiles/files/53140781435.pdfIn PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/12847797302.pdfIn PDF document text
    • https://perleyparish.org/wp-content/plugins/super-forms/uploads/php/files/579b8f91ccc35fa6f0a93947aab2341b/pajanozilixerusajevafu.pdfIn PDF document text
    • https://prestinireedcorp.com/userfiles/files/fupaledoluvusanikusa.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137a583a3005---rozexuzokowiwopovopos.pdfIn PDF document text
    • http://anbuadidravidarmatrimony.com/ckfinder/userfiles/files/52141536672.pdfIn PDF document text
    • https://arbormaster.net/uploads/files/wefawezetezuwekope.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_off0000d95f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD95F 17780 bytes
SHA-256: 3b80203517a7ea4b63923ac357b36a65509d8690e48c2b362280733db56e595d
font_01_sfnt_off00010767.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10767 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011f7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F7E 10220 bytes
SHA-256: af1b6f7efa54ce9a60d3f8225408dd92ada67f415539d9a94b3bd10d9d9365a8