Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f89d6fadfbdd3f…

MALICIOUS

PDF

85.9 KB Created: 2021-09-02 08:54:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 5f2ac5c79226405d9391cabab6f7db6d SHA-1: d8a916dd5fc81643fa5f559c7725c358575f7864 SHA-256: 81f89d6fadfbdd3f21e7f64e95202818a74f4f0b4b2de366c762e17f30a7fbee
96 Risk Score

Malware Insights

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

The ML classifier strongly indicates maliciousness, and the PDF contains numerous external URIs pointing to compromised CMS uploads and disposable hosting. These links likely serve as a link farm to redirect users to malicious sites, potentially for phishing or malware delivery. No scripts were extracted, and the document body was unreadable.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 5

  • 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://crysiq.ru/uplcv?utm_term=cockroach+parts+name PDF link annotation
    • http://www.psstrecno.sk/wp-content/plugins/formcraft/file-upload/server/content/files/16073fe12afe28---66162000520.pdfIn PDF document text
    • http://www.farparts.cl/wp-content/plugins/formcraft/file-upload/server/content/files/16075635aa97a8---45849826233.pdfIn PDF document text
    • https://alexandrapanayotou.com/web/images/static/file/julijodidefumiwupuz.pdfIn PDF document text
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16118df0b1f17e---66920397930.pdfIn PDF document text
    • https://atlanthealth.com/wp-content/plugins/super-forms/uploads/php/files/b7308d3cfdd240d351a9066c14b25f41/kexite.pdfIn PDF document text
    • https://csom.cz/wp-content/plugins/super-forms/uploads/php/files/c29e5a69e82cb98bdd9db211f2c52a6d/fowababopewus.pdfIn PDF document text
    • https://kvgrup.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160d5d33aef3d3---82246783558.pdfIn PDF document text
    • http://amphorabeautyclub.com/campannas/file/24142657199.pdfIn PDF document text
    • http://kiddeefire.com/media/userfiles/files/50903549687.pdfIn PDF document text
    • http://xn--42-6kcdlkbomh7beggito5p.xn--p1ai/userfiles/file/jenev.pdfIn PDF document text
    • https://civilkontroll.hu/uploads/file/zawibaxomukinigorovo.pdfIn PDF document text
    • http://infrabud.eu/fckpliki/file/86082669773.pdfIn PDF document text
    • http://zekidilektekstil.com/images_upload/files/mipinusumenozojobojuter.pdfIn PDF document text
    • https://xrtradingfeedback.com/cmsimages/file/75110172871.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071b059b5547---949805162.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/161048fe2097cc---warulaz.pdfIn PDF document text
    • https://www.theknowledgeonline.com/files/lib/ckfinder/userfiles/files/27374269347.pdfIn PDF document text
    • https://asiatravel.kg/wp-content/plugins/super-forms/uploads/php/files/79b7f0355b186e8170e7b77d38837bed/70349574742.pdfIn PDF document text
    • http://jcbcharpentebois.com/ressource/site-image/files/45754529892.pdfIn PDF document text
    • http://rzn-house.ru/upload/file/14429930739.pdfIn PDF document text
    • http://bibliotekaludwin.pl/img/upload/files/17796913370.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/ca283c7a33bdb34fde79afcc1f9e9ffb/mutobudasawosuwomuzudoza.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_off0000ec07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC07 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001041e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1041E 10624 bytes
SHA-256: c5e528c09f161e5a2fc2f049983f0873c31bee4d819efae6577b93fe10d7b767
font_02_sfnt_off00011c48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C48 17680 bytes
SHA-256: 2802a4ea2855ad6b30e91843fe70f82e9c26be53f2dd45643a21bc49ded120ce