Malicious PDF — malware analysis report

Static analysis result for SHA-256 a41d851a8975d1a8…

MALICIOUS

PDF

76.8 KB Created: 2021-09-15 14:28:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: cd5134b705bc453235dc5ad588d3e875 SHA-1: 2beed6e1c7387c70cb5a2a17463094177c7b61e1 SHA-256: a41d851a8975d1a8aa56b1662e8f821b16fa3d1eeecea4e5c8acb03ed9968bf1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. While no scripts were explicitly extracted, the PDF structure and link farm behavior suggest an attempt to lead users to malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9914

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://biznesfishki.ru/files/userfiles/files/nofiregefarexobup.pdf
    • https://ehbo-oostkapelle.nl/userfiles/file/94772530271.pdf
    • http://njbeihang.com/uploadfile/file///2021090222080682.pdf
    • https://nepaltrekkinginhimalaya.com/assets/userfiles/files/duvanokikutovamesalet.pdf
    • http://yourmoneyyourbank.com/uploads/File/98642324417.pdf
    • http://sonhanint.com/uploadpic/sun/files/202109061609596187.pdf
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138e97fd4552---68698173670.pdf
    • http://fratellibeninca.com/images/file/89586021080.pdf
    • http://appinaris.net/ckfinder/userfiles/publics/files/wadigubizolenikolokuji.pdf
    • https://study-abroad-travel.com/ckfinder/userfiles/file/berufunojakolatad.pdf
    • https://swimproject.eu/wp-content/plugins/super-forms/uploads/php/files/2c004eab1d93367ceada21d75b91ce93/legosevalusifopo.pdf
    • http://4bx.pl/public/file/48507723834.pdf
    • http://angelofthewinds.net/ckfinder/userfiles/files/vidujutisimuwu.pdf
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e046ba6d6d.pdf
    • https://banderlogclub.ru/Files/file/60024130172.pdf
    • http://tonioloclaudio.it/userfiles/files/66932032528.pdf
    • http://visit-pune.com/userfiles/file/wakopikesejimasoxomenoda.pdf
    • http://chinahongji.com/d/files/xuvogu.pdf
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/16137a21b3422c---budapemewoxesi.pdf
    • http://pampa.be/uploads/userfiles/files/93289584608.pdf
    • https://dolnoslaskialarmsmogowy.pl/imgturysta/files/7212561963.pdf
    • http://wecans.net/_UploadFile/Images/file/sunorewonekelanatuxiboles.pdf
    • https://tucarrorentacar.co/ckfinder/userfiles/files/davad.pdf
    • http://cokhiminhhien.com/media/ftp/file/kusopoli.pdf
    • http://nextgenship.net/upload/file/20210910163124810386.pdf
    • https://www.lire-les-notes.com/ckfinder/userfiles/files/22486463420.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=little+more+chris+brown+download
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000bdfb.bin
26eb43504b3faeda1ba21357a8575b96224adc1e0d7e3cde308cb3cabec32f6d
pdf-font-stream PDF embedded font (sfnt) at offset 0xBDFB 10820 bytes
font_01_sfnt_off0000d6c6.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD6C6 16792 bytes
font_02_sfnt_off0000eed8.bin
6fac7d088fbe7b30d1432295ec642fed870a29de8a3e0f2226776e35ef04d6de
pdf-font-stream PDF embedded font (sfnt) at offset 0xEED8 19744 bytes