Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c91e33761c2aba1…

MALICIOUS

PDF

89.1 KB Created: 2021-08-18 05:38:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 1ef5cc4ed56c64dbd874f874a12ca340 SHA-1: a7ab62671aa2fbc91b8c85d7496d1363176fff3b SHA-256: 5c91e33761c2aba186ad72848c6e9ce45fb075f181d22799be899754394b7ab5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many hosted on compromised WordPress sites, suggesting a link farm used for phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent. Although no scripts were explicitly extracted, the PDF structure and embedded links are indicative of malicious activity, likely leading to a second-stage download or redirection to a phishing page.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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 http://vstarmp.cn/upload/files/20210710_105838.pdf In PDF document text
    • https://maugli24.ru/wp-content/plugins/super-forms/uploads/php/files/29b8ec9ea5026b5dcde6093a91275d27/15081007572.pdfIn PDF document text
    • https://razdolle.by/wp-content/plugins/super-forms/uploads/php/files/2gif61skj5hka1q31dtpakl296/tiwododuribetotejavimap.pdfIn PDF document text
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/28d0e2760c9195f2523b6d2e57144e14/gigoxabava.pdfIn PDF document text
    • https://trsbarriersdirect.com/wp-content/plugins/super-forms/uploads/php/files/etohesfop0dajd60s779bjr9dh/napuxujazetazanaki.pdfIn PDF document text
    • http://omniatel.it/wp-content/plugins/formcraft/file-upload/server/content/files/160745ea470cff---45532292651.pdfIn PDF document text
    • https://www.keystonecare.co.uk/wp-content/plugins/super-forms/uploads/php/files/1400930042d1bb612160083df40a6c7b/xenelat.pdfIn PDF document text
    • http://carriewoodfamily.com/clients/5/5b/5b9f2fb360c4065436fb7fe1267c3612/File/33464834688.pdfIn PDF document text
    • http://dharmapremipariwar.org/userfiles/file/nikizalimudi.pdfIn PDF document text
    • https://genimmigration.com/viking1/uploads/files/sozobi.pdfIn PDF document text
    • http://aodaibooking.com/FileData/ckfinder/files/20210608_F96476B3D906002B.pdfIn PDF document text
    • https://cargobull.cz/res/file/88748812488.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ace7cd3cff0---xolulepasuluvejifewiwi.pdfIn PDF document text
    • http://adabaskimerkezi.com/upload/file/12165719579.pdfIn PDF document text
    • http://score1forspencer.com/clients/4/45/4587145e2679cb7673d0e21b436e5c25/File/17708244549.pdfIn PDF document text
    • https://bostoncake888.com/UserFiles/files/96411373164.pdfIn PDF document text
    • http://cn-polylysine.com/d/files/74851491306.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c58e507dd84---mikofomewuwaboref.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16106a8958b382---senanatiwadusukupudawelo.pdfIn PDF document text
    • http://kristenpell.com/userfiles/files/fapewawemezoxel.pdfIn PDF document text
    • https://nicemexico.net/wp-content/plugins/formcraft/file-upload/server/content/files/160c206ab008ef---fusesurufuxulokazevogo.pdfIn PDF document text
    • https://economiadecomunion.net/ckfinder/userfiles/files/55640012518.pdfIn PDF document text
    • https://www.azembay.com/wp-content/plugins/super-forms/uploads/php/files/g5s8at6sl6ei6b0p7hp20r9vu0/zixesurepewujuk.pdfIn PDF document text
    • https://bbensonmft.com/wp-content/plugins/super-forms/uploads/php/files/6e2735c1d39ca3bea9d475c85b0b3078/15770965149.pdfIn PDF document text
    • http://petraifevronii.ru/ckfinder/userfiles/files/32790201972.pdfIn PDF document text
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610d77e331b19---76213809964.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=us+navy+rtc+recruit+training+guidePDF 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_off0000f66b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF66B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010e82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E82 10668 bytes
SHA-256: b7194225288c7ff1ebec2dd9cfe89cde02d2cccafeceedf3e146bf6dfe123905
font_02_sfnt_off000126eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126EB 17152 bytes
SHA-256: 5ca4d94e7a1e098ec6d6dcf727294f41a5a9f04aaef344ceb2915fa8c0c0da16

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