Malicious PDF — malware analysis report

Static analysis result for SHA-256 df3b89c05da742f7…

MALICIOUS

PDF

79.9 KB Created: 2021-09-18 10:08:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f336eccf47c6dcf18a36562bb09fc634 SHA-1: 00f018642d0191216f7e731d9857d40fdb00a73f SHA-256: df3b89c05da742f7fd6c1c20197e73833d233d18d7f31ea6401cf8f3bbabbb27
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate the file functions as a link farm, directing users to compromised WordPress upload storage and other disposable hosting sites. The embedded URLs, such as 'https://coretry.ru/uplcv?utm_term=email+to+send+to+employer+with+resume', likely serve as lures for phishing or to download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://coretry.ru/uplcv?utm_term=email+to+send+to+employer+with+resume PDF link annotation
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1613af73017227---wapezu.pdfIn PDF document text
    • https://fong-cai.com/upload/files/migudixijakusa.pdfIn PDF document text
    • http://gidaero.com/upload/fckeditor/file/wagedejepowazekisabizodes.pdfIn PDF document text
    • http://dryoucosmeceutical.com/userfiles/files/75531314648.pdfIn PDF document text
    • http://kietminhrivet.com/upload/files/lutosewovulunosotoziperev.pdfIn PDF document text
    • http://quangcaosmsgiare.com/media/ftp/file/14014386675.pdfIn PDF document text
    • http://krr-nfe.com/suratnfe/UserFiles/File/35150438878.pdfIn PDF document text
    • http://www.greenfield-sustainability.com/images/files/jusukawo.pdfIn PDF document text
    • https://vnjhanoi.com/upload/files/43257937372.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/16142b303ee56a---46475972007.pdfIn PDF document text
    • https://portsidestrategies.com/wp-content/plugins/super-forms/uploads/php/files/a02ba8ec10919eb7f2ceacce02d861d5/91136660477.pdfIn PDF document text
    • http://imobilestore.de/userfiles/file/29761735732.pdfIn PDF document text
    • https://stmpallet.com/ckfinder/userfiles/files/30676943422.pdfIn PDF document text
    • https://kaemsp.org/upload/editor/file/90709227098.pdfIn PDF document text
    • https://cncunse.com/d/files/47895928708.pdfIn PDF document text
    • http://arablift.net/userfiles/file/dalosunitakitekomese.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f6ccb0685f---zejewekagirif.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16139c003a4a63---72519337700.pdfIn PDF document text
    • http://prodottoitalia.eu/userfiles/files/87059891088.pdfIn PDF document text
    • https://khachsan295doson.vn/namthuan/images/news/files/50510112203.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_off0000d281.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD281 18100 bytes
SHA-256: 7cac254a46c30471969f7bba64c634218bf4c9d55f9d8fee9569b47b9a2dbcf3
font_01_sfnt_off00010139.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10139 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011950.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11950 10940 bytes
SHA-256: 2579a49671e5e6f9ae82d3f536df486a9b5875f473278e973dc08c93563538f6