Malicious PDF — malware analysis report

Static analysis result for SHA-256 23707a9bd5658532…

MALICIOUS

PDF

81.8 KB Created: 2021-07-03 19:02:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 8c529b868029a2861d2e9762caf08c40 SHA-1: abeeb6dab88ec578938661777d174ad0ff9c7f02 SHA-256: 23707a9bd5658532353a09733d1b24b0033b2fd7d7f7cf890a9f52fd0727cd11
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript and a large number of external URIs, many hosted on compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate maliciousness, specifically phishing. The embedded JavaScript likely facilitates the redirection or further payload delivery, while the link farm on compromised sites serves as a lure to trick users into clicking malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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=types+of+correspondence+in+math PDF link annotation
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081f734598b8---nufozekupanapebodesezib.pdfIn PDF document text
    • https://minutesnap.com/wp-content/plugins/super-forms/uploads/php/files/30ce21f9d585261cdc9a45c9335c1771/negufuwijoxuruletax.pdfIn PDF document text
    • http://mundori.com/js/ckfinder/userfiles/files/tisipuve.pdfIn PDF document text
    • http://szsahsh.com/uploads/files/89789127633.pdfIn PDF document text
    • http://pansophers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad21ccd3c54---59907896180.pdfIn PDF document text
    • https://iescolumbus.org/wp-content/plugins/super-forms/uploads/php/files/ee9b9c73d2281247b849cde11a7a92ad/97828121543.pdfIn PDF document text
    • http://rethabise.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160a67e02b2169---19785159688.pdfIn PDF document text
    • https://www.jedeminute.de/wp-content/plugins/super-forms/uploads/php/files/9ub1lsolv6k0183hiqstlcfvrf/73237504766.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/phuo7uhi1pi0f715u88bsdvm7i/55592627283.pdfIn PDF document text
    • http://www.itbaloch.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073dcac1c618---rubumigilap.pdfIn PDF document text
    • https://kolbandibileklik.com/resimler/files/sidopojexasom.pdfIn PDF document text
    • https://an-professional.ru/img/files/file/pijamexadama.pdfIn PDF document text
    • https://polskieplytki.com/wp-content/plugins/super-forms/uploads/php/files/a8a50c8c528ea3707754ac50896dbe7e/84116428564.pdfIn PDF document text
    • http://www.segurosfacility.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c9b0eb69e95---nefinem.pdfIn PDF document text
    • http://daehwa.info/uploaded/file/zuxizobivunasevenigu.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d1df2c49a0---jubifibazimolumaj.pdfIn PDF document text
    • http://wchs65.org/clients/b/bb/bb65574a37642f7fe3135935df861e67/File/gufegazewamunakajujebaki.pdfIn PDF document text
    • http://bezpieczna-strefa.pl/wp-content/plugins/super-forms/uploads/php/files/a761966759f73f2bb75722bbe02d5bbc/bivedi.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b62c25a1f6e---jutodagulifajinawu.pdfIn PDF document text
    • https://k9-warrior.com/wp-content/plugins/super-forms/uploads/php/files/de67lv1490hg3226ve6rav3kkd/febitogebaverufor.pdfIn PDF document text
    • http://www.allatpatikapecs.hu/images/file/18766170430.pdfIn PDF document text
    • http://test.uebersetzungen-nesselberger.de/wp-content/plugins/formcraft/file-upload/server/content/files/160879d08ac15f---xepuwakugojokokisodilewe.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_off0000dd39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD39 17036 bytes
SHA-256: 99e38176cc41283ecefed37361cb170a5e9dd07e530287ab4d8a8d1f7baf9808
font_01_sfnt_off00010917.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10917 10916 bytes
SHA-256: 6d8ea6e9a078cfc41611bced946b717e558a9a4992839e350380e002b6954cb3
font_02_sfnt_off0001223b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1223B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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