Malicious PDF — malware analysis report

Static analysis result for SHA-256 3919752e5f22ebee…

MALICIOUS

PDF

80.7 KB Created: 2021-09-18 05:17:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8f479308c15593bd16cc600fbb8caf6e SHA-1: 3f8b16eed879b672492be296d1af541bf0cd974e SHA-256: 3919752e5f22ebee412883888ba317597fbb9d8eb7c1f8d0acf23fb6a532f218
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with multiple heuristics indicating it functions as a link farm. The embedded URLs, such as https://crewmak.ru/uplcv?utm_term=setup+exchange+on+android, likely lead to phishing sites or malware downloads. The PDF structure and the nature of the URLs suggest an attempt to lure users to external resources, consistent with a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 https://crewmak.ru/uplcv?utm_term=setup+exchange+on+android
    • http://www.dadosefatos.net.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613b133e5ac7c---lijepakelawaz.pdf
    • http://agt.es/files/galeria2/files/63358385715.pdf
    • http://carrozzeriabosini.net/userfiles/files/70533156319.pdf
    • http://mp-hd.de/data/aktualnosci_imgs/file/jilisukelivoviragejaz.pdf
    • http://studiofantino.it/userfiles/files/fobusisuvojerubawimex.pdf
    • http://cnsgawefgl.netsociality.com/upload/files/53769456163.pdf
    • http://www.urbanwaterways.info/files/gonobu.pdf
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1612f4567efb51---fexavewoduzebim.pdf
    • https://machnik.net/ckfinder/userfiles/files/negip.pdf
    • http://ahjygjg.com/upload_fck/file/2021-9-13/20210913192246498664.pdf
    • https://magyar-logyogyasz.hu/fileok/file/55557424424.pdf
    • http://phunphu.com/userfiles/file/xatebubupofovigaxif.pdf
    • https://soi.icami.mx/ckfinder/userfiles/files/xukazutirisosuniw.pdf
    • https://guclupin.com/calisma2/files/uploads/73040250957.pdf
    • http://apartamentykunickiego.pl/architekci/public/upload/ckfinder/userfiles/files/12233587435.pdf
    • http://encino.kopanramen.com/uploads/files/68055551729.pdf
    • https://zoomkish.com/basefile/zoomkishcom/files/bilasabowuw.pdf
    • http://wwm-quanta.com/upload/files/88433172198.pdf
    • https://glycocalyx.nl/userfiles/image/file/47652895974.pdf
    • https://fzclicks.com/demo/files/editor/file/7300684276.pdf
    • https://bohemiamaestro.com/webpagebuilder/ckfinder/userfiles/files/majomulonubutu.pdf
    • https://www.beadvised.co.uk/wp-content/plugins/super-forms/uploads/php/files/4e5a187f22e458ded5c7e02c5e94171c/gemolaxagegosir.pdf
    • https://astoriareiki.com/wp-content/plugins/super-forms/uploads/php/files/4044700ca12fda7056db8bbfa62d0496/wafafobawopiw.pdf
    • https://fleuriste79.fr/ckfinder/userfiles/files/64391989850.pdf
    • 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_off0000d6e8.bin
93c921e37b3ecbf50e97308fbcb0764e6fcaf478c62d1d563b639851b0f67d36
pdf-font-stream PDF embedded font (sfnt) at offset 0xD6E8 10856 bytes
font_01_sfnt_off0000efb8.bin
475809587f8a8044e1779be536ee609af531365729845cbf371589fc059c32f8
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFB8 17928 bytes
font_02_sfnt_off00011da3.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11DA3 16792 bytes