Malicious PDF — malware analysis report

Static analysis result for SHA-256 086cd21b0de10a86…

MALICIOUS

PDF

85.9 KB Created: 2021-08-03 04:08:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 43a48ce0db8aeb0b9ea2cf2a821cf111 SHA-1: dcaf0cc9e92dab089397364d39702b8bb0062777 SHA-256: 086cd21b0de10a86e7d40d71a9383e2b5a525cc078efe3b6aa1d0a66e23aae9c
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as Pdf.Phishing.Trojan. The presence of numerous links pointing to compromised CMS upload storage and disposable hosting suggests a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://rentbucharest.net/images/userfiles/81919447922.pdf In PDF document text
    • https://akemi.ro/hirek/file/47300065988.pdfIn PDF document text
    • https://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/am4e9uqujg73lo6op6i9slcs0j/46218686147.pdfIn PDF document text
    • http://dailycan.com/userfiles/files/53145374404.pdfIn PDF document text
    • http://perfectthesale.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078b089d99d1---32010326103.pdfIn PDF document text
    • http://mtcongnghiepxanh.com/upload/fckimagesfile/pijinetosowosawerulopu.pdfIn PDF document text
    • https://arrad.ch/modules/ck/ckfinder/userfiles/files/zugokoridewupupamitu.pdfIn PDF document text
    • https://howardsteeves.com/wp-content/plugins/super-forms/uploads/php/files/f7aaa8e9413868479334081ba6c209ab/gijavisudofojusuxi.pdfIn PDF document text
    • https://serpavenger.com/ckfinder/userfiles/files/kefilogetefedoxot.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/ef955702a8f5a4ece22c1556eeb4bccb/tojita.pdfIn PDF document text
    • https://ceccargiurgiu.ro/userfiles/file/68648434937.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/rslmn76qferjec0c7dp5f8ph5m/rosasefelud.pdfIn PDF document text
    • http://valifyrepapillon.com/clients/6/68/68e1c6a84db99a04c21676ff826d6e37/File/banimimej.pdfIn PDF document text
    • http://anonelectronics.com/admin/fckeditor/editor/filemanager/connectors/php/upload_jpg/file/202106292014309103.pdfIn PDF document text
    • http://theydeserveastamp.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607dd719d4f8a---38160540237.pdfIn PDF document text
    • https://people11people.gr/uploads/File/90183640618.pdfIn PDF document text
    • http://www.firengo.com/userfiles/files/rorarowaluvubeki.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160906ac9bf173---33252177679.pdfIn PDF document text
    • http://www.sensible-seeds-premium.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a84d293dbd6---levuwefatafubifotesuwo.pdfIn PDF document text
    • http://elskup.pl/images/assets/file/93512948796.pdfIn PDF document text
    • http://centrlita.ru/archive/image/file/ritixazimidojawetud.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161004e802c71f---votowovudikujupekifijujof.pdfIn PDF document text
    • http://e-district.org/userfiles/file/3505919554.pdfIn PDF document text
    • http://juniorsmagazine.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089ed1395d56---nefopopiderazubororis.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=sample+authorization+letter+for+electricity+connectionPDF 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_off0000ed66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED66 10924 bytes
SHA-256: 97f639e01fb4d84abd68ae76026963d0271f8e4f01661dd270e4e34141215979
font_01_sfnt_off00010692.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10692 16300 bytes
SHA-256: 8ef5c2ac6690084447b0dd167b57b41409c67014fa57b278a34475f40cf9679c
font_02_sfnt_off0001308e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1308E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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