Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f37356d838aeb2d…

MALICIOUS

PDF

69.8 KB Created: 2021-09-02 13:26:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 7553c299362f91a87a9e9280318c636a SHA-1: f0416c8789a7077e80488e57171ab931ba52067c SHA-256: 4f37356d838aeb2d34ff26a4242bb10743b9d1b28e12cfc598fae35c6f114e9a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to disposable hosting or compromised CMS upload directories, indicating a link farm designed to redirect users to malicious sites. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the PDF structure itself is indicative of a malicious lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://garglob.ru/uplcv?utm_term=n+acetil+l+cisteina+pdf PDF link annotation
    • http://lyzebrno.cz/userfiles/file/marudomoja.pdfIn PDF document text
    • https://itandem.net/ckfinder/userfiles/files/60816036308.pdfIn PDF document text
    • http://kruengrangthai.com/files/files/62582487478.pdfIn PDF document text
    • https://otoform.com/upload/ckfinder/files/sugut.pdfIn PDF document text
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/48a5a46b5a07e571fe7e847f4e5bb2a7/litezikuveligofizepis.pdfIn PDF document text
    • https://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/5480a04420f9a4c70966cf0797b61eb4/bupekuximixu.pdfIn PDF document text
    • https://avela.md/userfiles/file/35374340227.pdfIn PDF document text
    • http://agenziaimmobiliarecannavo.eu/userfiles/files/wumupovunaxisigidur.pdfIn PDF document text
    • http://dtyxbpzx.com/filespath/files/20210823235258.pdfIn PDF document text
    • http://kstarsmall.net/userfiles/file///kelowukunerev.pdfIn PDF document text
    • https://dailyhondaotomientay.com/upload/files/39135292395.pdfIn PDF document text
    • https://amenajarisiconstructii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16079d1c66f96d---27605217206.pdfIn PDF document text
    • http://nowyhotelik.pl/userfiles/file/54939153775.pdfIn PDF document text
    • http://www.whirlpool-beachcomber.at/wp-content/plugins/formcraft/file-upload/server/content/files/1607a4133b0a69---40497898767.pdfIn PDF document text
    • https://glbtrader.com/userfiles/file/pisipifu.pdfIn PDF document text
    • https://allcondosales.rodeodrivecondosale.com/userfiles/files/84090170499.pdfIn PDF document text
    • http://freeski.hu/freeski/file/pajerezun.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1609a96553d6fa---73476464409.pdfIn PDF document text
    • https://sevsport.info/wp-content/plugins/super-forms/uploads/php/files/246f67c047dd07cb3d1a15622e278f33/17235026793.pdfIn PDF document text
    • http://wijnhuis-vaessen.nl/site/data/ws/files/33208473027.pdfIn PDF document text
    • http://computerdoki.hu/user/file/ziluz.pdfIn PDF document text
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/9095f09a71db8244d4b4025d6659c75e/ziverivi.pdfIn PDF document text
    • http://www.skup.it/wp-content/plugins/formcraft/file-upload/server/content/files/160d8e76737f86---73653818132.pdfIn PDF document text
    • http://phubozena.pl/userfiles/file/36983503161.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_off0000b231.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB231 10372 bytes
SHA-256: ac375d5e38ae4f69162bd2bfba4bd1500da8937c6c985e7baba5fb892137cef7
font_01_sfnt_off0000c9b8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9B8 15652 bytes
SHA-256: 5959db593c6c320ac68116824cf0b36174f8d262cae7411baba4ba273f3117f8
font_02_sfnt_off0000f1ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1EF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1