Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a8f10fad5043a06…

MALICIOUS

PDF

81.4 KB Created: 2021-09-21 16:15:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 45783a5cc8cc56f595c6cba2ea39eac2 SHA-1: baa1acef42cbcbdbc52c5485f3697ebd64a736d4 SHA-256: 8a8f10fad5043a0603b79c84f1b0dc1210c4be4f0054772877c0f6ceea91eed0
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and links to compromised WordPress uploads, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. The document body is heavily obfuscated, preventing a detailed analysis of its specific lure, but the presence of multiple external links points to an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://ketchas.ru/uplcv?utm_term=how+to+change+font+style+of+phone PDF link annotation
    • https://chung-pei.com/userfiles/file/vijuzilibojifa.pdfIn PDF document text
    • http://www.saraviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/161467d14aa46c---37073301522.pdfIn PDF document text
    • http://phannhan.vn/files/usersfiles/files/27775384666.pdfIn PDF document text
    • https://undergroundtakeout.com/userfiles/file/segobojupedajewitunabojo.pdfIn PDF document text
    • https://sealand-pptc.com/userfiles/file/kazerofefim.pdfIn PDF document text
    • http://ahkjt.com/upfile/file/42675959931.pdfIn PDF document text
    • https://pecintajp.com/contents/files/nanerinegarumusugew.pdfIn PDF document text
    • https://hightechrustremovers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161465dcd0fee0---mebivupurawopuwenuzumiri.pdfIn PDF document text
    • http://olympicthesportshop.in/uploads/gudusimifof.pdfIn PDF document text
    • http://gesundimjob.at/images/content/files/zapadofox.pdfIn PDF document text
    • https://braveathlete.net/geektic/files/17429505660.pdfIn PDF document text
    • http://www.laterveer-biesenbeek.nl/ckfinder/userfiles/files/mabun.pdfIn PDF document text
    • http://yourhealthyanswer.com/ckfinder/userfiles/files/78329783318.pdfIn PDF document text
    • http://csc0898.com/userfiles/file/20210901071507_4b2uni.pdfIn PDF document text
    • http://medicapoland.pl/uploaded/file/17584968094.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136f9942e33e---kemulivumor.pdfIn PDF document text
    • http://kristiankutschera.de/userfiles/file/pelevage.pdfIn PDF document text
    • https://lightupalife.org.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161447c66973a2---66403571642.pdfIn PDF document text
    • http://knowleangling.co.uk/ckfinder/userfiles/files/83464827071.pdfIn PDF document text
    • http://jumpstart.mobi/userfiles/file/82848842063.pdfIn PDF document text
    • http://linklandhotels.com/upfile/editor/files/35743912884.pdfIn PDF document text
    • http://eubeer.vn/uploads/files/tawavuzikunupozedepimebot.pdfIn PDF document text
    • http://fusen-es.info/yamituki-n/uploads/files/gegafijir.pdfIn PDF document text
    • http://alumcity.ru/userfiles/file/82105762229.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_off0000da10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA10 17580 bytes
SHA-256: 3bb293232c4c37ef7652ae4d79bbc52507394b81a810a4319bd82209d81c8833
font_01_sfnt_off00010765.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10765 10756 bytes
SHA-256: ad51f248f9b36f267d265ed0b67e90fcf4143e979586d5462eeaa3a5a3d2582a
font_02_sfnt_off00012032.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12032 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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