Malicious PDF — malware analysis report

Static analysis result for SHA-256 91b8c487831bd65d…

MALICIOUS

PDF

79.0 KB Created: 2021-09-21 22:58:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: d0342d2367b78014388b940b3f5b1709 SHA-1: e76fd0ea7fd08e4e4402d20ef33dda8114d7cf31 SHA-256: 91b8c487831bd65d2592484e507e5129e8af3a18851708d374945bbf5bddb114
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to compromised websites or disposable hosting, indicating a link farm designed to redirect users. ClamAV detected this file as 'Pdf.Phishing.Trojan', and the ML classifier also flagged it as malicious. The presence of multiple external URIs and a link farm structure strongly suggests a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://infrive.ru/uplcv?utm_term=sunset+live+wallpaper PDF link annotation
    • http://gzky.cn/dubeite/ckfinder/userfiles/files/20210913_112149.pdfIn PDF document text
    • https://valserve.in/web/k/main_admin/ckfinder/userfiles/files/mozigutolowunexunapeluzu.pdfIn PDF document text
    • http://unixsensor.com/uploads/files/202109212250029646.pdfIn PDF document text
    • http://akiisushi.com/uploads/files/zugerifejitelusoteb.pdfIn PDF document text
    • http://bk-plus.at/userfiles/files/mowedebinusofurusuf.pdfIn PDF document text
    • https://worldkelo.com/wp-content/plugins/super-forms/uploads/php/files/a39d177e70868717e4eb0c50ba31580c/84407627677.pdfIn PDF document text
    • https://www.spoton.pet/wp-content/plugins/super-forms/uploads/php/files/viu0lso7kkv6vakpgu2vv85l3a/zamimojakuzodud.pdfIn PDF document text
    • http://remobudostol.pl/pliki/51449370061.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/db4f22402ffc2ede4dd749ecf2d733b6/dujoxi.pdfIn PDF document text
    • http://finalbrand.cz/upload/file/5653264684.pdfIn PDF document text
    • http://ip-malkov.ru/uploads/files/natifiv.pdfIn PDF document text
    • http://haohanlegend.com/Uploadfiles/files/kirerarep.pdfIn PDF document text
    • https://growlocals.com/wp-content/plugins/super-forms/uploads/php/files/b446bdc1b51fa226ccfb64b0eb4333fc/xaxajupitaxug.pdfIn PDF document text
    • http://www.northern-japan.com/image/upload/File/getomobekumuf.pdfIn PDF document text
    • http://polesprogettazioni.com/userfiles/files/kidowutaguzawuranofoxus.pdfIn PDF document text
    • https://bikidi.com/UpFiles/WebEditorFiles/file/82747197465.pdfIn PDF document text
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/16146ace47b557---motosovobuxesujibidotak.pdfIn PDF document text
    • http://hamdannepal.com/userfiles/file/pikeret.pdfIn PDF document text
    • http://dgone.kr/userfiles/file/20210914133047.pdfIn PDF document text
    • http://babijie.com/upload_fck/file/2021-9-13/20210913141732858675.pdfIn PDF document text
    • https://songhong.info/userfiles/file/resirujamenofojisozejaba.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e520a73b59---budoxagumudeb.pdfIn PDF document text
    • https://weborder.cloud/userfiles/file///tarenobevoriz.pdfIn PDF document text
    • http://coumert.com/images/file/64916368537.pdfIn PDF document text
    • http://mictrogiang.com/userfiles/files/mufoporesakake.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_off0000d1d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1D0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e9e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9E2 17016 bytes
SHA-256: efa5f47ba317554c92dd140326d1ee77d4b35978b810f10fa3df58680f9003d1
font_02_sfnt_off00011618.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11618 10452 bytes
SHA-256: 2ab9c6f8f7d02d5548b0c55ff735f5e69dd2e7aa2575c0d2f0c8e7212e5b8e23

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