Malicious PDF — malware analysis report

Static analysis result for SHA-256 4157e496dda8a19a…

MALICIOUS

PDF

85.1 KB Created: 2021-10-05 14:56:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: c7a305ef076c403e3af16202a621bf2f SHA-1: 761c4c118698724f7b08821ec16322268b1bad2f SHA-256: 4157e496dda8a19a0c259c73ff022f352017bda7a38028ae0f76cc2219bbaed8
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 pointing to various domains, many of which are associated with compromised CMS uploads or disposable hosting. The ML classifier strongly indicates maliciousness, and the structure suggests a link farm designed to redirect users to potentially harmful content. No scripts were extracted, but the URL distribution itself is the primary attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://philabc.ru/uplcv?utm_term=every+music+note+name PDF link annotation
    • http://nceed.kr/pds/userfiles/files/lesiluzud.pdfIn PDF document text
    • http://woonhuislift.info/wp-content/plugins/formcraft/file-upload/server/content/files/16141aac27ca7c---mabimunen.pdfIn PDF document text
    • http://saigondome.com/uploads/userfiles/file/65992394935.pdfIn PDF document text
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613667810be1d---16659428694.pdfIn PDF document text
    • http://alda.pl/ckfinder/userfiles/files/49307214827.pdfIn PDF document text
    • https://arte-salon.ru/upload_picture/vinatopozefuwunoxivu.pdfIn PDF document text
    • http://www.verneteco.com/ckfinder/userfiles/files/wageropidarokekan.pdfIn PDF document text
    • http://generaldistco.com/images/file/wigotorax.pdfIn PDF document text
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1614841363c5e1---17190574856.pdfIn PDF document text
    • http://metalzilembo.it/userfiles/files/xejazodabureserubiv.pdfIn PDF document text
    • http://thamdinhgiadaiquang.com/img/files/lexiwamapanexewibada.pdfIn PDF document text
    • http://www.sname.org.tw/sname/ckfinder/userfiles/files/78150651961.pdfIn PDF document text
    • http://safiorida.dk/operatori/userfiles/file/56211373426.pdfIn PDF document text
    • http://humanconsulting.cz/media/file/26978903772.pdfIn PDF document text
    • https://foundationkuzmanov.com/files/14231145099.pdfIn PDF document text
    • http://ifaistos.reality.gr/~triantaf/images/file/90572714797.pdfIn PDF document text
    • http://infinity-pro.ru/userfiles/file/befaguvamefenavelor.pdfIn PDF document text
    • http://cachnhietwin.com/luutru/files/lusopawosavope.pdfIn PDF document text
    • https://thefertilizergranulator.com/d/files/dopor.pdfIn PDF document text
    • https://royal-art.pl/uploads/userfiles/files/lisisa.pdfIn PDF document text
    • http://fmmvn.net/userfiles/files/zanedonubawix.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_off0000e577.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE577 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fd89.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD89 19148 bytes
SHA-256: f64fce166d53dbdce5557dcf6cad6dbe07f0abb4fe400a4cb1531e24e09a66bc
font_02_sfnt_off00012eb5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12EB5 10608 bytes
SHA-256: 20c1ad5d0b9c63d6458d588b0744e9c057a3e492228f9077c5e37a229ed1fa1b