Malicious PDF — malware analysis report

Static analysis result for SHA-256 53cb492c8d58c13e…

MALICIOUS

PDF

95.0 KB Created: 2021-07-30 14:12:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: c67f3aa43e90dd6a946bcfc132228212 SHA-1: 0f5bc370efdb09ebddff8a3811b2a01c7faef742 SHA-256: 53cb492c8d58c13e0525eefa50dbd9ed0af6845ef072e9c9822f6a682bafbaa8
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to various websites, some of which host other PDFs. The heuristic 'SE_PASSWORD_ARCHIVE_LURE' suggests a common tactic to bypass gateway scanning by encrypting payloads, which are then intended to be decrypted by the user, likely leading to further infection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/397e4c7bc6d6bc2f2dd7a0f3888346b9/65345932134.pdf In PDF document text
    • http://thaoduocvn.com/userfiles/image/file/folezemon.pdfIn PDF document text
    • http://www.elsecretodelolivo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8a491d4f5a---zorojedepe.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/f8d3caf5d9e2be0f52975460ee9b96a2/bazalutewepevun.pdfIn PDF document text
    • https://idd.no/ckfinder/userfiles/files/netamutotekafutirigawum.pdfIn PDF document text
    • https://emilline.dk/ckfinder/userfiles/files/tonepesonejar.pdfIn PDF document text
    • https://flvirginia.com/wp-content/plugins/super-forms/uploads/php/files/f9a1b923ac84e19bc70735cfc3f44cd8/duzapox.pdfIn PDF document text
    • https://northstarexecutivesearch.com/wp-content/plugins/super-forms/uploads/php/files/eb4f8cc77bef016f95ee98e612ed1acd/55959167591.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081021be0eba---dusokil.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160a6c4721662d---19405171783.pdfIn PDF document text
    • https://soechi.net/userfiles/file/nenivanobo.pdfIn PDF document text
    • http://omni-links.com/images/blog//file/73427809562.pdfIn PDF document text
    • http://titadoorbinhduong.com/upload/files/fevesotabimo.pdfIn PDF document text
    • http://kukubara.com/zdjecia/file/vibotixi.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/146f03398d52a3a868b7976fbf47a633/tajumetowaxesejawinewija.pdfIn PDF document text
    • https://rumputhijau.com/contents//files/3025764979.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/427b19ef123ba24bbb021dc7227cb3cc/sepikas.pdfIn PDF document text
    • https://www.lang-mayer.de/wp-content/plugins/formcraft/file-upload/server/content/files/160d6720a0bfde---38321946896.pdfIn PDF document text
    • https://bibliotheque-des-arts.ch/ckfinder/userfiles/files/vewufoxetogunobovazemebot.pdfIn PDF document text
    • http://uceng.net/_UploadFile/Images/file/davugibanogenawor.pdfIn PDF document text
    • https://www.rydalmereprestige.com.au/wp-content/plugins/super-forms/uploads/php/files/u10jgmolp8ffmn0boelsour79d/zuwujifadigeka.pdfIn PDF document text
    • http://mq-water.net/upload/julewusiv.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075ec4d32958---povulujejis.pdfIn PDF document text
    • http://curry-box-deluxe.de/userfiles/file/funub.pdfIn PDF document text
    • https://www.truemark.dev/DevelopersIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=java+interview+questions+and+answers+for+freshers+pdfPDF 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_off00010afb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AFB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012312.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12312 10936 bytes
SHA-256: 356454c8d7503d6ce0c011fc3329831a362bf92ddf40eb76809e974020bb1056
font_02_sfnt_off00013c3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13C3D 18932 bytes
SHA-256: 5655151a7ed6ba9191d1d28bf917ca062b823c8729942e8b95298647c40f1760

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