Malicious PDF — malware analysis report

Static analysis result for SHA-256 6c76cdcf261b3989…

MALICIOUS

PDF

70.9 KB Created: 2021-09-25 23:26:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: da69eaeaf830731898fcc24b4497fc69 SHA-1: 2acb12edfa91f2b19ab52961cae369ef440b79d8 SHA-256: 6c76cdcf261b3989b090c0fa132ca3fcc3c9829dd2b40aee5e3db62b0ab703d7
96 Risk Score

Malware Insights

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

The PDF file contains numerous external URIs and link farms pointing to various websites, many of which are hosted on compromised CMS upload storage. The ML classifier strongly indicated maliciousness, and the structure suggests an attempt to lure users to potentially malicious sites. No scripts were extracted, limiting the analysis of direct execution vectors.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://oniceh.ru/uplcv?utm_term=machine+learning+in+bioinformatics+pdf PDF link annotation
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/7091ed62582f61886c4f0221e64d7258/bikuze.pdfIn PDF document text
    • http://dieukhactransam.com/uploads/files/52261062703.pdfIn PDF document text
    • https://md-bud.pl/szklo/photos/file/22491105888.pdfIn PDF document text
    • http://ewtch.com/upload/files/gexogom.pdfIn PDF document text
    • http://wolfroccatiassociati.it/userfiles/files/pezibidabigivojesot.pdfIn PDF document text
    • https://kicksomeglass.com/wp-content/plugins/super-forms/uploads/php/files/06c9b510f32ee58307758d3a10a215af/90639175877.pdfIn PDF document text
    • http://joltiy.ru/uploads/files/94396782360.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614947d757543---35004395286.pdfIn PDF document text
    • http://zhfangyuan.com/uploadfiles/files/zetisuruga.pdfIn PDF document text
    • http://comlark.ru/userfiles/files/xuvomidonefogovututenewu.pdfIn PDF document text
    • http://konberdbio.com/upload/files/vigemosewevaxut.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1614d2094be6f2---95908149641.pdfIn PDF document text
    • http://medicom.pl/userfiles/file/17661191212.pdfIn PDF document text
    • http://sushrutproctology.org/ckfinder/userfiles/files/50172296447.pdfIn PDF document text
    • http://iuf.kr/pds_down/files/11344445328.pdfIn PDF document text
    • http://vitalenzyme.com/uploads/fckupload/file/9069636315.pdfIn PDF document text
    • http://pro-group.ru/userfiles/files/wapidufegevugakapuzis.pdfIn PDF document text
    • https://freshchannels.com/home/sites/freshchannels/public_html/ckfinder/userfiles/files/gawaratamunekeluku.pdfIn PDF document text
    • https://rainbowfurnitures.com/files/files/20752358583.pdfIn PDF document text
    • https://locktactyuma.com/userfiles/file/54280160200.pdfIn PDF document text
    • https://mimpishio1bet.net/contents/files/60393588625.pdfIn PDF document text
    • http://eltdb.com/UserFiles/files/90218769978.pdfIn PDF document text
    • http://maychebiengoduykhuong.com/media/ftp/file/92925277723.pdfIn PDF document text
    • http://dienlanhtruongson.com/upload/files/86674753571.pdfIn PDF document text
    • http://novo-foto.ru/ckfinder/userfiles/files/80531307147.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_off0000b47c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB47C 15496 bytes
SHA-256: 7517911ffba87edd3b32f07a295f90a8d286fd60c0af0934a4b3bb0cd04ca1ef
font_01_sfnt_off0000dc13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC13 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f42a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF42A 11200 bytes
SHA-256: 6ebdd55c9d669d78165f1c1c8808b918a64a378697ff502f6ee5ff808b2f42da