Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f836e891e2ab65a…

MALICIOUS

PDF

72.0 KB Created: 2021-09-21 07:42:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 4e57818f7175b66c8c7ac755bf6d5b61 SHA-1: 4238e34b2b35a9aedcc12f0144162177b17fe541 SHA-256: 8f836e891e2ab65a347ba6f43ef52b9c2c8191ba66eec5a17cc8dc1265adb831
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs that form a link farm, a common tactic for phishing or distributing malware. Heuristics indicate these links point to compromised CMS uploads and disposable hosting, suggesting a malicious intent to obscure the true destination. The ML classifier and ClamAV detection strongly support the malicious classification.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

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://jlgardner.org/home/jlg/public_html/ckfinder/userfiles/files/29773666212.pdf In PDF document text
    • https://sambelteri.com/contents/files/58605453376.pdfIn PDF document text
    • http://wxhsbl.com/ckfinder/userfiles/files/20210911_185551.pdfIn PDF document text
    • http://ipayon.com/root/FCKeditor/file/34001442191.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/4c5d452a958a31bf1ae6716de59bad58/jafikupimowo.pdfIn PDF document text
    • http://viprealestatebrokers.com/userfiles/files/61457123260.pdfIn PDF document text
    • http://mosjob.ru/images/file/dosekopidobadedenuxipuwav.pdfIn PDF document text
    • http://mail.me.ntou.edu.tw/ckfinder/userfiles/files/20210916_180145.pdfIn PDF document text
    • https://cleanenergy.mn/uploads/files/senudipezofusinise.pdfIn PDF document text
    • http://nct-vn.com/userfiles/file/zigujimubotunosu.pdfIn PDF document text
    • https://ibexquimica.com.br/ckfinder/userfiles/files/19112792193.pdfIn PDF document text
    • http://2safe4u.cz/UserFiles/File/dulagalusejaverufadike.pdfIn PDF document text
    • https://tradingphrases.net/userfiles/files/17274483143.pdfIn PDF document text
    • http://sochi-riba.ru/ckfinder/userfiles/files/5729236123.pdfIn PDF document text
    • http://ambvetbrashersclavoghisu.eu/userfiles/files/zeluji.pdfIn PDF document text
    • http://cs-golfclub.com/ckupload/files/33935933747.pdfIn PDF document text
    • http://villahetzwartepaard.nl/survey/userfiles/files/zewovozidiza.pdfIn PDF document text
    • https://biroestarsa.hu/uploads/file/numuteregexomazar.pdfIn PDF document text
    • http://omniatel.it/wp-content/plugins/formcraft/file-upload/server/content/files/16145072f06ae1---jonetonisewoverawiguwevu.pdfIn PDF document text
    • https://bikeid.net/ckfinder/userfiles/files/33039461157.pdfIn PDF document text
    • http://gzcil.com/uploadfile/files/sitavisinitamawupeselokum.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/604bc9f0eb30df857089e72a92b21d6e/88790621777.pdfIn PDF document text
    • https://ewdel.cz/ckfinder/userfiles/files/baxefalur.pdfIn PDF document text
    • http://igs.compcierge-asia.com/ckfinder/userfiles/files/modowukes.pdfIn PDF document text
    • https://torrentclub.vip/wp-content/plugins/super-forms/uploads/php/files/n8d1v3f756jdgi319vjeoigd6r/sobepewawoboraxad.pdfIn PDF document text
    • https://educhina.mn/editor/files/revofiraxok.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=do+i+have+to+play+nioh+1+before+nioh+2PDF 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_off0000ba7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA7F 15212 bytes
SHA-256: 3888e582c9e3c919739c6ca2d3401c97390f416240f4faf72451a17eba9b9637
font_01_sfnt_off0000e0ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0FF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f916.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF916 10780 bytes
SHA-256: 93dfb1d70f1a3cfa1f7a75bf177897b402e8ca6ac38269342f9d4bf58051f54a