Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a6d3da9abcca28b…

MALICIOUS

PDF

121.0 KB Created: 2021-06-24 23:28:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 10a4c3be9a7a9fba34f6f2baf4633c21 SHA-1: 284382008131373fa534dc532a6ded2e19a76c2d SHA-256: 4a6d3da9abcca28b943d266ad62fc1ba71efd3b2726b3a5ae8a3aa15878004a8
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Several heuristics indicate the PDF functions as a link farm, pointing to multiple compromised WordPress upload directories and disposable hosting sites. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, but no clear textual lure is present.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bd0a11bd18d---18563304189.pdf In PDF document text
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094076bd6173---ziginowanipodupip.pdfIn PDF document text
    • http://adance0112.com/upfile/editor/file/zaxikusoxomaroderit.pdfIn PDF document text
    • http://emannsltd.com/userfiles/zavazuwiburozaf.pdfIn PDF document text
    • http://kapelski.pl/userfiles/file/30187345886.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b046f023383---87554984484.pdfIn PDF document text
    • https://ofertaromania.ro/ckfinder/userfiles/files/51930538700.pdfIn PDF document text
    • https://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/46b6243f9f4ec7371fb5ba8d40329b5f/zirelikajozagotepus.pdfIn PDF document text
    • https://roweryelectra.eu/app/webroot/uploads/file/16200937975788.pdfIn PDF document text
    • http://veraschwemmle.de/fckdata/file/82027436270.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/cd0b7a25992aee42bfe69caa998b23d3/vepijes.pdfIn PDF document text
    • http://automsystem.com/UploadFile/file/20210513031712667.pdfIn PDF document text
    • https://drainscovers.com/wp-content/plugins/super-forms/uploads/php/files/9ad1980ec7185480a06bf13f1153bbf6/56099324045.pdfIn PDF document text
    • https://hssipm.com/wp-content/plugins/super-forms/uploads/php/files/a3c5abd2652931e92cbe0df5822baa7b/fenujoneluvoz.pdfIn PDF document text
    • https://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/bfff7ca04b47e6f1b6073a1e158a05ed/pubanibulonikafedazol.pdfIn PDF document text
    • https://sellos-mecanicos.com/wp-content/plugins/super-forms/uploads/php/files/00c287d22b8a28b302e6f009e96a39f4/36708950524.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=smash+bros+newcomer+fontPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00016506.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16506 10920 bytes
SHA-256: ec2be68fba18fff2577eb9ec7a1993b740bca98da376cc601acd4c57c03ce594
font_01_sfnt_off000188da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x188DA 5424 bytes
SHA-256: 9f412d2bd6985303d0c1232ae6bc96b312223a31c7d383a4bcda5228747d6fe3
font_02_sfnt_off00019b2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19B2F 4892 bytes
SHA-256: 97cbd3405db98ce33fdc0047d13104f0eee2f46bc8fb9cbd0061c745d334a1d0
font_03_sfnt_off0001acdc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1ACDC 12384 bytes
SHA-256: a5d4e986ac9626cf0886b67fb62542ee315b4b630419bbda8e1948906525b9d9

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