Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9ba3e2bfb44b698…

MALICIOUS

PDF

74.3 KB Created: 2021-09-22 16:28:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 179e5b4f5ae94d58f0f06530b08c028c SHA-1: 94994ec12ada0732947b29cf00c85315b3a14a91 SHA-256: a9ba3e2bfb44b6988771a6ea51b775256db9fd6f3e8bcc5289d0a06725ded255
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised CMS upload directories or disposable hosting. The ML classifier strongly indicates maliciousness, and the link farm structure suggests an attempt to lure users to malicious content or distribute further payloads. The presence of multiple PDF files hosted on compromised sites indicates a likely distribution mechanism via spearphishing attachments.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://nusantarabet4d1.com/contents/files/51196986977.pdf In PDF document text
    • https://accuratesearch.com/userfiles/file/tekaw.pdfIn PDF document text
    • https://etonbio.com/newsLetters/images/file/58116396065.pdfIn PDF document text
    • http://townofwinslowin.com/flash/townofwinslowin.com/file/35679744697.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/a291d37b6b44c7d3c347d8df6380cfa8/suzejisesajifokimuvezepew.pdfIn PDF document text
    • http://bienbao.net/uploads/files/bawijeza.pdfIn PDF document text
    • https://xedulichhaiphong.vn/images/news/files/buwon.pdfIn PDF document text
    • https://a1-recruitment.fr/v2011/Files/fck_upload/file/44528091959.pdfIn PDF document text
    • http://friluftsgruppen.se/wp-content/plugins/formcraft/file-upload/server/content/files/16138a840e6861---717061232.pdfIn PDF document text
    • http://aspbae.org/userfiles/file/53260445240.pdfIn PDF document text
    • http://cwpni.com/userData/ebizro_board/file/texujejadakazutanax.pdfIn PDF document text
    • http://navrattan.co/userfiles/file/85980455709.pdfIn PDF document text
    • http://srihemkuntsahibfgp.org/hemkunt/userfiles/file/21044650283.pdfIn PDF document text
    • http://xn--c1aejbdnke.xn--p1ai/admin/ckfinder/userfiles/files/jufugixajirixeripefazipo.pdfIn PDF document text
    • http://www.colegiometa.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/1614406b6ced2f---82813441935.pdfIn PDF document text
    • http://raylutickenterprises.com/userfiles/files/69639177374.pdfIn PDF document text
    • http://fine-cottage.ru/userfiles/file/bizositerodegijorudiv.pdfIn PDF document text
    • http://www.depomatrial.com/file/83641751009.pdfIn PDF document text
    • https://stabiactiv.com/userfiles/file/45618140729.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613abec7cc566---72645421265.pdfIn PDF document text
    • http://hiroi-es.info/yamituki-n/uploads/files/zujunezuloje.pdfIn PDF document text
    • http://dom-2000.ru/ckfinder/userfiles/files/gofasenidi.pdfIn PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/l4qonkearadj922rl3d2tcb5k5/14165718271.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=medial+s+blends+word+listPDF 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_off0000c1a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1A2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d9b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9B9 10460 bytes
SHA-256: 873da37493eb2474e4b8456773c6bd0ab5176676735644ccfeb053915f901f93
font_02_sfnt_off0000f19e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF19E 16204 bytes
SHA-256: 98c1258468c4fb19431186b7d8ec482888e5dd7bab00c75c82cf9408ba46ee4c