Malicious PDF — malware analysis report

Static analysis result for SHA-256 da11fc43a96289f8…

MALICIOUS

PDF

81.9 KB Created: 2021-09-12 23:46:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: b771ea96a78d76bf2c3dd59a9b4ac66b SHA-1: 3a57f217c469679a0ca638922262d70d2342ce0c SHA-256: da11fc43a96289f8496f99719cd51e34217b318e47995d9ae5bd284e1ed6aa0a
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many of which are hosted on disposable domains, suggesting a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically points to this behavior. While no scripts were explicitly extracted, the presence of embedded URLs and the overall detection suggest it is designed to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://crysiq.ru/uplcv?utm_term=aluminum+atomic+radius PDF link annotation
    • http://revistaspontan.ro/assets/ckfinder/core/connector/php/uploads/files/20495776914.pdfIn PDF document text
    • http://pass38.com/images/contentimages/files/71683442924.pdfIn PDF document text
    • http://jwconsult2005.com/file_media/file_image/file/59408365807.pdfIn PDF document text
    • http://www.scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/8700091451.pdfIn PDF document text
    • http://mobilesamara.com/img/files/file/7696335151.pdfIn PDF document text
    • https://profm.hu/files/file/61707458734.pdfIn PDF document text
    • https://hanyauntuktesting.com/contents/files/9756054698.pdfIn PDF document text
    • http://giaydantuongphongkhach.net/images/news/file/1209295718.pdfIn PDF document text
    • http://redactron.com/userfiles/file/74950157899.pdfIn PDF document text
    • https://vcubusinesssolutions.com/userfiles/file/27343953364.pdfIn PDF document text
    • http://packturf.fr/files/57337679581.pdfIn PDF document text
    • http://geometracosentino.com/userfiles/files/kekegabixaji.pdfIn PDF document text
    • http://permagnet.com/upload_files/file/21090612132740709555ye8t.pdfIn PDF document text
    • http://ecohort.com/userfiles/files/73346227170.pdfIn PDF document text
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16135aa27cc172---63156622699.pdfIn PDF document text
    • http://pengyou-english.com/FileData/ckfinder/files/20210905_DF45A0F562094C9A.pdfIn PDF document text
    • https://xn--hjrnskadeakademien-mtb.se/userfiles/file/8063472533.pdfIn PDF document text
    • http://kant21.com/userData/board/file/70307016635.pdfIn PDF document text
    • http://burchiellati.com/file_fck/file/tasozizi.pdfIn PDF document text
    • https://dalnoboy.com/data/filestorage/upload/files/96512427082.pdfIn PDF document text
    • https://frigosztufi.ro/ckfinder/userfiles/files/wewasemajugoliwer.pdfIn PDF document text
    • http://acevina.com/webroot/img/files/vixiwuzurat.pdfIn PDF document text
    • http://bukhatirhomes.com/userfiles/file/kereduvegizenexilujupiwe.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_off0000dc4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC4D 10480 bytes
SHA-256: 6d2bed07b574b7069d512e69ba8e729d7aebd6385658384274cf5060bd211a88
font_01_sfnt_off0000f40e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF40E 17596 bytes
SHA-256: 72389bae4bc275f7cbb97596fe934ce46313f52adc57b31c6cf32e520a524dcc
font_02_sfnt_off000121f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121F7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1