Malicious PDF — malware analysis report

Static analysis result for SHA-256 99834b8158249c8a…

MALICIOUS

PDF

82.9 KB Created: 2021-09-24 00:13:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 2334b05aded11874e510fe9293209a1d SHA-1: ef6888905b2e456028af533ba30cff1e0de4e235 SHA-256: 99834b8158249c8a61716f942abede17ebe1e8a2dc05dc4ef1d35cf34c100f02
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document flagged by multiple heuristics and a machine learning classifier as malicious. It contains numerous embedded URLs pointing to potentially malicious domains, suggesting a phishing or malware distribution lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a link farm strategy, common in phishing campaigns. Although no scripts were explicitly extracted, the PDF structure itself likely facilitates the redirection to these external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://nomylo.ru/uplcv?utm_term=how+long+does+a+fridge+have+to+sit+after+laying+down PDF link annotation
    • https://vinasimex.com/uploads/file/20222650638.pdfIn PDF document text
    • http://lynxauto.ru/userfiles/file/97754594524.pdfIn PDF document text
    • http://rhoptik.cz/klienti/devel/sneznerolby.cz/ckfinder/userfiles/files/58291035215.pdfIn PDF document text
    • http://bajkolandia-leszno.pl/userfiles/file/10803919074.pdfIn PDF document text
    • https://master.plus/wp-content/plugins/super-forms/uploads/php/files/3a09b64b39f47655556c7c1762bf9997/11171537815.pdfIn PDF document text
    • https://hinodecoder.com/userfiles/file/mubekadalolatexabab.pdfIn PDF document text
    • https://westhigienia.hu/editor_up/tinepukipazumu.pdfIn PDF document text
    • https://atx-stroy.ru/wp-content/plugins/super-forms/uploads/php/files/3775c41f3b0254ad2895ecb29e096814/20402074120.pdfIn PDF document text
    • http://klaaswester.nl/img/file/24678491347.pdfIn PDF document text
    • http://jyjjapan.jp/files/ckeditor/files/retopizewaviredafu.pdfIn PDF document text
    • https://limblength-sldf.com/userfiles/file/pifuligaxamix.pdfIn PDF document text
    • https://jjcfurnituremaker.com/userfiles/files/dozixalidixa.pdfIn PDF document text
    • https://www.servicespace.org/inc/ckfinder/userfiles/files/goxenolenawizivegul.pdfIn PDF document text
    • https://jajugroup.com/ckfinder/userfiles/files/77225484469.pdfIn PDF document text
    • https://digireg.ch/upload/5816448207.pdfIn PDF document text
    • https://lbk-ingatlan.hu/uploads/file/dusafox.pdfIn PDF document text
    • https://ichapps.com/ichapps/ckeditor-ckfinder-integration/uploads/files/67156994756.pdfIn PDF document text
    • https://eastoncn.housemember.com/uploads/files/legavagujuselone.pdfIn PDF document text
    • http://odumakus.com/uploads/files/48042756607.pdfIn PDF document text
    • http://pjcwyy.com/upload/file/tisuminavurarolapuxuwema.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_off0000e031.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE031 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f843.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF843 17208 bytes
SHA-256: e2441591d9c5bddcc68ac2e2f18f3d05660da576d3c1891f68876ec49a0ade41
font_02_sfnt_off000124ba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124BA 10888 bytes
SHA-256: 206b61785f62de2f6e4695d249e79b34284efc6a58c90ee90fc74876a155970d

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