Malicious PDF — malware analysis report

Static analysis result for SHA-256 88831d7f2d691034…

MALICIOUS

PDF

92.1 KB Created: 2021-07-26 09:51:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: f67792f2fca7bdd68295f41495d35475 SHA-1: 816a8be956eab6c2cef0a46b102d065d9bbe6bbf SHA-256: 88831d7f2d691034e02c4667c3285bf4d437e604a7503e0ed405ccb0a16ce73b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1190 Exploit Public-Facing Application

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple compromised WordPress upload directories and other unknown hosts. The presence of numerous PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM firings strongly suggests a phishing or malware distribution campaign leveraging these compromised sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 https://www.kngroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078cded1a3c8---10749626695.pdf In PDF document text
    • https://morabia.fi/images/file/koxikigeto.pdfIn PDF document text
    • http://trainternational.in/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8feea583e---82840401207.pdfIn PDF document text
    • http://sochi-polyana.com/ckfinder/userfiles/files/zosigitoguza.pdfIn PDF document text
    • https://www.xcelsus.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609c04154f2a3---nomopefodib.pdfIn PDF document text
    • https://wilsonbarrera.com/inicio/wp-content/plugins/formcraft/file-upload/server/content/files/160a4fcebdb1b0---96701780912.pdfIn PDF document text
    • https://www.focus.mu/wp-content/plugins/super-forms/uploads/php/files/ad01289b08d2800d477aac9d0610d8d9/4215121319.pdfIn PDF document text
    • https://kachhiproperties.com/wp-content/plugins/super-forms/uploads/php/files/sh6clgpq8feme8c82kddrb4423/52839679921.pdfIn PDF document text
    • http://i-daa-wl.de/userfiles/linugedoxurel.pdfIn PDF document text
    • https://mylodge-naoshima.com/nijavobolatopanov.pdfIn PDF document text
    • http://chi-kara.net/userfiles/file/3344421238.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/4344a0ffabfd4bb553cec7f5287de886/81038847985.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/lbumne7kn3maiige693dcdfb45/50905325846.pdfIn PDF document text
    • https://anthonygillant.com/userfiles/file/13348973724.pdfIn PDF document text
    • http://forglass.sk/userfiles/file/bomufaxotipusewiriru.pdfIn PDF document text
    • http://prplus4u.com/ckupload/files/posulen.pdfIn PDF document text
    • http://0965818789.com/CKEdit/upload/files/64528087867.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077dd69da606---buwofidexukapiduxobame.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/wefufijirida.pdfIn PDF document text
    • http://totaleclipsenv.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082a17285ce9---jetemanaxizej.pdfIn PDF document text
    • https://www.kindspring.org/inc/ckfinder/userfiles/files/25691603965.pdfIn PDF document text
    • https://kalitelivideoizle.com/resimler/files/12323565375.pdfIn PDF document text
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16076281c12ccd---lubogujatapuxaneketa.pdfIn PDF document text
    • https://thinkhigh-tech.com/d/files/dorepepobufemixovodanix.pdfIn PDF document text
    • https://thepainter.asia/upload/files/3394268693.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=odin+sphere+mercedes+guidePDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fb96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB96 2196 bytes
SHA-256: a2ab34cb12473915ae10549671e0ad310edf4b795b374108428ce9fee9a4fcc9
font_01_sfnt_off0001057b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1057B 16884 bytes
SHA-256: 6518924a1833f752fcf2d23dae9a468c56bfbc82aabfd49fe0bf961ca93546ec
font_02_sfnt_off0001319f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1319F 10660 bytes
SHA-256: 34044f1be2e6256a80cd694ff4cb3d8e3c72e2141f8ead19a411dc512e4a99fc
font_03_sfnt_off000149a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x149A3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1