Malicious PDF — malware analysis report

Static analysis result for SHA-256 aae28e7848a0a743…

MALICIOUS

PDF

82.9 KB Created: 2021-09-23 22:21:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 768040e23550a1bb86f50e8c0bb59a29 SHA-1: 35c428f6f8c4323ab305c663e159ccb5f6861c3f SHA-256: aae28e7848a0a7438a405254aa7c00d59410c5037034827ad26b91ee1224798c
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to potentially compromised WordPress sites or disposable hosting, indicating a link farm strategy. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple external URI heuristics further supports its malicious nature. The document body is heavily obfuscated and unreadable, preventing a more detailed analysis of its specific intent beyond being a distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://silver1979.com/upload/file/pegud.pdf In PDF document text
    • https://tedesco.pl/userfiles/file/xarejoza.pdfIn PDF document text
    • https://habrit.tw/ckfinder/userfiles/files/43857903404.pdfIn PDF document text
    • http://almawred-sy.com/files/adminfiles/files/88562048861.pdfIn PDF document text
    • http://studiotecnicoligioni.com/userfiles/files/vufate.pdfIn PDF document text
    • http://duda-tech.pl/dudatech/upload/file/xurogimuritofuwiponevir.pdfIn PDF document text
    • https://onlineadda.organicemall.com/ckfinder/userfiles/files/31052800511.pdfIn PDF document text
    • http://mastera-mix.ru/ckfinder/userfiles/files/93179174490.pdfIn PDF document text
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/16130ebdf47c14---batorufuji.pdfIn PDF document text
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/161496b521fe97---83472977756.pdfIn PDF document text
    • http://isagenixmakessense.com/ckfinder/userfiles/files/rugekubemekoroguzizefi.pdfIn PDF document text
    • http://polymer-optix.de/userfiles/file/79939781455.pdfIn PDF document text
    • http://zelene-centrum.cz/webpagebuilder/ckfinder/userfiles/files/44926939374.pdfIn PDF document text
    • http://www.mbk-montage.nl/ckfinder/userfiles/files/46626612387.pdfIn PDF document text
    • http://yeosingol.com/FileData/ckfinder/files/20210914_056766B231A51690.pdfIn PDF document text
    • http://autoservizimensi.it/images/fck/file/kamivuradavu.pdfIn PDF document text
    • http://klick-tipp.info/ckfinder/userfiles/publics/files/1041720056.pdfIn PDF document text
    • https://vizzzio.ru/wp-content/plugins/super-forms/uploads/php/files/ddb2132701eb60e82ffb094ad1f1773a/tepakakavetibiros.pdfIn PDF document text
    • http://bienbao.org/uploads/files/44796712182.pdfIn PDF document text
    • http://yenidenyuzlendirme.com/ckfinder/userfiles/files/21447092248.pdfIn PDF document text
    • http://doingthing.com/downloads/blog/geust/files/47229167316.pdfIn PDF document text
    • http://donaldnathanlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/17717563158.pdfIn PDF document text
    • http://assessmentinsight.com/ckfinder/userfiles/files/rakozozovemitivamizuzaf.pdfIn PDF document text
    • http://zhongjiukeji.com/upload_fck/file/2021-9-23/20210923200007994996.pdfIn PDF document text
    • https://asi-filter.pl/files/file/nenasawovoguzamaluxame.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=nba+apk+2019PDF 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_off0000e101.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE101 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f918.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF918 10056 bytes
SHA-256: 6f35d6332b26f68716e913c85c28007a91438d43991e6106b60427bdfe8780ce
font_02_sfnt_off00010f64.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F64 18096 bytes
SHA-256: 97a76bc16d17fc1f80c3fa34c51750edfd2ee3b99532aa75da1bf205b3c4b245