Malicious PDF — malware analysis report

Static analysis result for SHA-256 b158304e3efe4e33…

MALICIOUS

PDF

76.0 KB Created: 2021-08-28 09:49:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 87d9195d640dae09b33ada0834c2ca2d SHA-1: 812b3947d85010b4655a536a4b405fb8c5e0e047 SHA-256: b158304e3efe4e33d6022370512052f8a0a4cd9bee88f9a7500a824b38d1f525
156 Risk Score

Malware Insights

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

The file is a PDF identified as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs pointing to potentially compromised websites or disposable hosting. The presence of multiple external URIs and link farm heuristics suggests an intent to redirect users to malicious sites, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

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://philabc.ru/uplcv?utm_term=erisa+insurance+requirements
    • https://www.enviedecrire.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be4e04aaad3---gamef.pdf
    • https://nsck-cykelmotion.dk/userfiles/file/3390578883.pdf
    • http://coutleelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/parirenebupazebixu.pdf
    • http://praguetransfer.com/files/file/wuwubazijoxejuzuvigused.pdf
    • http://coatsofarms.com.au/ckfinder/userfiles/files/suxerevanoxufevibigapufe.pdf
    • https://petroblend.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c72f8ceab4a---sinitiwawabitenutejadi.pdf
    • http://mulroyenvironmental.ie/userfiles/file/wiwewu.pdf
    • http://masonhn.com/d/files/gamubibozulubafidisami.pdf
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160b75f6d700b1---worepasobifipogu.pdf
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f5714524b9d---roraxita.pdf
    • http://kiuruvedenlukio.fi/tiedostot/file/48232730040.pdf
    • http://lesura.net/userfiles/file/89321406132.pdf
    • https://fotojursa.cz/userfiles/file/42378033557.pdf
    • https://susta.vn/userfiles/file/salivaxalutujepijeporagot.pdf
    • http://abwpetersburg.com/uploads/files/rebavamanafixuwas.pdf
    • https://kopari.hu/files/file/60595037683.pdf
    • http://rocincorporated.com/domain.com/images/dynamic_pages/file/lojizedovivepumewexo.pdf
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c318e98efae---bunitategezofodukozo.pdf
    • https://ksi-system.pl/editorfiles/file/wisasesoragudelofoj.pdf
    • http://dermalab.pl/userfiles/file/suzotanigikinibisodi.pdf
    • https://keralahappyjourney.com/ckfinder/userfiles/files/muwupavuluzu.pdf
    • http://autoscuolecasetta.it/userfiles/files/zilafedewavilututema.pdf
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/6b364669390478f78942f6f2fe0d67f4/25133659642.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c782.bin
b41b2088dbd21526f964de20bde58a4750d765b8c0f8051d7ac4cbdc1d09d77b
pdf-font-stream PDF embedded font (sfnt) at offset 0xC782 10456 bytes
font_01_sfnt_off0000df33.bin
935c7176f2ba51ef462e1b2ebb5ce55ca67d2c73a1e2fbc6512a8cce2c3ca57b
pdf-font-stream PDF embedded font (sfnt) at offset 0xDF33 16328 bytes
font_02_sfnt_off0001094c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1094C 16792 bytes