Malicious PDF — malware analysis report

Static analysis result for SHA-256 3885c75c75be0d3d…

MALICIOUS

PDF

85.3 KB Created: 2021-09-08 18:58:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f26963610cfd4d5b8992463e35b43976 SHA-1: 6d46007e8aca3bd6ab396093a5a020d0b03e6bf3 SHA-256: 3885c75c75be0d3daff3ab7c4c27ece9afc1cb6d8a82386dcf50c1f9ace1b4ef
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, indicating a link farm designed to host malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. No scripts were extracted, but the PDF structure itself is indicative of a malicious lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://krisoc.ru/uplcv?utm_term=green+hills+compiler+user+manual+pdf PDF link annotation
    • http://www.webtony.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161315b07077ca---57299415274.pdfIn PDF document text
    • http://cosmosimpex.com/app/webroot/ckfinder/userfiles/files/gefodijogos.pdfIn PDF document text
    • http://xn--365-pn7mwb654m2qn.com/ckupload/files/1663416624.pdfIn PDF document text
    • https://irisapp.cn/uploadfiles/fckeditor/20210901/file/16305052405832.pdfIn PDF document text
    • https://ewastexperts.com/userfiles/files/65231807955.pdfIn PDF document text
    • https://tort-art.ru/userfiles/file/xobajixowizidisux.pdfIn PDF document text
    • https://ibshospitals.com/userfiles/file/22117689004.pdfIn PDF document text
    • http://tulga.ru/editor/files/49028917107.pdfIn PDF document text
    • https://www.fangjin.org/ckfinder/userfiles/files/91072393570.pdfIn PDF document text
    • https://cradlegold.com/wp-content/plugins/super-forms/uploads/php/files/remknac6n0atf8bt4mv3t8ubre/53252004573.pdfIn PDF document text
    • http://rujiahk.com/uploadfiles/file/93980471788.pdfIn PDF document text
    • http://packamate.com/userfiles/wubilatavaresazanu.pdfIn PDF document text
    • https://mattweidnerlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613418ef9c4d4---xiwisudikufumegil.pdfIn PDF document text
    • http://konditsionery-odincovo.ru/upload_picture/file/kesavuwuwa.pdfIn PDF document text
    • http://lednotice.com/userData/board/file/sojedovuridimiriw.pdfIn PDF document text
    • https://study-abroad-travel.com/ckfinder/userfiles/file/87832821557.pdfIn PDF document text
    • https://beldaoyun.com/calisma2/files/uploads/49511085454.pdfIn PDF document text
    • http://knx-shop.ru/admin/ckfinder/userfiles/files/vekegazugupegipasalij.pdfIn PDF document text
    • http://hitelesen.com/userfiles/file/purez.pdfIn PDF document text
    • https://rosewoodcity.org/nbloom/fckuploads/file/sexenovakajokige.pdfIn PDF document text
    • http://hanart21.com/files/userfiles/file/11800622234.pdfIn PDF document text
    • http://braghieriarchitettura.com/userfiles/files/mojojanofosufijulel.pdfIn PDF document text
    • http://sdds.be/userfiles/file/7802454785.pdfIn PDF document text
    • https://encouragingmath.com/wp-content/plugins/super-forms/uploads/php/files/7f460992a4ed7fae663d751517174e39/varul.pdfIn PDF document text
    • http://avandcie-energy.com/ckfinder/userfiles/files/8980501118.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_off0000e738.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE738 10928 bytes
SHA-256: 0e755767d7e65e8a30c21630f41c597fdd64fb73a8b3bbe528adb2eeb9e5b422
font_01_sfnt_off0001004b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1004B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001185d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1185D 17888 bytes
SHA-256: 8f163d7d29a52b62d4f3b47ed3e05915644b3372401a13a155d24e1005005612