Malicious PDF — malware analysis report

Static analysis result for SHA-256 373fb9de8fec8cc3…

MALICIOUS

PDF

81.2 KB Created: 2021-09-20 07:03:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 827c681c124bb325a2c2fbb3926c65ba SHA-1: c369704a700155f5a812c15581407086c23466fa SHA-256: 373fb9de8fec8cc3c135d1347b8abb3e4ab31450cba183daec6cada84880b1a4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Several extracted URLs point to compromised CMS upload directories, suggesting a distribution mechanism for further malicious content. The PDF structure and embedded links are indicative of a phishing or redirection attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://warsztatgdynia.pl/app/webroot/media/files/vafeparudutidejuj.pdf In PDF document text
    • http://dakdekkersindex.nl/images/uploads/48591111894.pdfIn PDF document text
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/161302cc33b879---29842079094.pdfIn PDF document text
    • http://abovomedia.hu/_user/file/49893526306.pdfIn PDF document text
    • https://sunarchegypt.com/userfiles/file/tekujagefe.pdfIn PDF document text
    • https://mvmdigital.gr/files/files/tubixivazinidufipu.pdfIn PDF document text
    • http://stalmont.eu/userfiles/file/tisasegewijifivizepobuti.pdfIn PDF document text
    • https://www.marbelitesa.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/161374bc97886e---99643574019.pdfIn PDF document text
    • https://fivetc.vn/uploads/files/poxewuzipolesud.pdfIn PDF document text
    • http://amy-tsai.com/images_express/userfiles/files/lekupatetaxatojedavevexi.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613da45a33d39---fesosegotofos.pdfIn PDF document text
    • https://fptica.ru/images/file/18401994132.pdfIn PDF document text
    • https://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/d401b061ea3876f045913025ea557db5/85984698869.pdfIn PDF document text
    • http://elcivan.com/admin/UserFiles/file/bipakodawelenafeg.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16131727cb31ee---laleta.pdfIn PDF document text
    • https://lombardpruszkow.pl/local/userfiles/file/34017237421.pdfIn PDF document text
    • https://bcbc3399.com/upload/files/53485646341.pdfIn PDF document text
    • https://srilangkapools.com/contents/files/bedimomimolawimawelilalu.pdfIn PDF document text
    • https://gad-elhak.com/userfiles/file/maxuwag.pdfIn PDF document text
    • http://schuetzenfest-hemeringen.de/ablage/userfiles/files/68791858535.pdfIn PDF document text
    • http://dalieuht.com/app/webroot/uploads/files/34594539482.pdfIn PDF document text
    • http://studiomilano.eu/userfiles/files/todadodiretade.pdfIn PDF document text
    • https://corpusbg.com/files/fck/file/woxopago.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=can+you+check+airpod+battery+on+androidPDF link annotation
    • 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_off0000d98b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD98B 17292 bytes
SHA-256: a32f5a7f29b31bd5839a463794505f0af196c7754b98379b6c25ad55b22facbc
font_01_sfnt_off00010668.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10668 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011e7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E7F 10876 bytes
SHA-256: 76c6b0e1e8b68dbb844d081dc6d15dfb8bdd4b0085e58f9df74adc6f80cf5785