Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d1c6bb78be13309…

MALICIOUS

PDF

124.7 KB Created: 2021-03-14 02:12:50 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: a51e1378b2b8620d1a9825821643548f SHA-1: df02fa23983f67807cf4f1d28d1585e103cb2396 SHA-256: 8d1c6bb78be133090bb072821a147989a7c81cf174130671585de37b879c6462
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file is classified as malicious by ClamAV and an ML model, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to numerous external URLs, including suspicious domains like 'xajibur.ru', under the guise of providing PDF downloads. The presence of multiple external links and the use of disposable hosting suggest a phishing or SEO spam campaign aimed at driving traffic to potentially malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://xajibur.ru/award?keyword=quantitative+seismic+interpretation+pdf+download PDF link annotation
    • http://about-fb-support.com/skyrim_mods_to_avoidd08kl.pdfIn PDF document text
    • http://businessoutsourcing.info/cadena_trofica_esta_formada_pork9jrx.pdfIn PDF document text
    • http://antonioit.fun/verb_forms_exercises_for_class_10arpni.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://6b137298-3864-41c5-aaa3-11744000c3c2.filesusr.com/ugd/b916f4_c21af5a720454a3bbf54f63d432e925b.pdf?index=trueIn PDF document text
    • https://297de083-771a-4730-a3b8-a2afe8c7d209.filesusr.com/ugd/47424f_6543750a7f7646f09c4fc871e4b48994.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/bee8e9f3-6699-4c95-aba0-4b1a7fe03ce6/how_to_write_a_good_lab_report_biology.pdfIn PDF document text
    • https://b9e1b105-38e0-4bbf-baad-90de1e2021e1.filesusr.com/ugd/432b07_bbe3a8973b4b423dab03984790c4fd3b.pdf?index=trueIn PDF document text
    • https://acfc0e76-311d-46af-9c13-f46c112eb424.filesusr.com/ugd/f90bad_503f34e86f1e47b58f922878d99e1541.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/tupofelasujewas/hong_kong_gmp_guidelines_for_pharmaceutical_products.pdfIn PDF document text
    • https://1a6c606f-1efd-495f-9370-57f425d809fd.filesusr.com/ugd/1be480_1468f69b6b164848a2f6e02bebc4e0ef.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/vosimalume/how_to_calculate_real_gdp_per_capita_using_nominal_gdp.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b9c8bb7e-3a18-4141-b1de-08f2e3f96d8b/57365946293.pdfIn PDF document text
    • https://c3a7a64c-5591-430b-94d7-c2eadfdf3523.filesusr.com/ugd/966478_b13b48bcc9834d9db1c3682c751b2a8e.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/e9f5cf34-e44d-496c-bd48-edb1650abc53/nupalimesuxo.pdfIn PDF document text
    • https://cb2d4818-2134-4ea5-ae57-1bc45cfc4292.filesusr.com/ugd/7e787c_0abb13a5dbd24b32bb7243cb8a34d520.pdf?index=trueIn PDF document text
    • https://ed59cdd8-0d75-4634-8bb2-7afdb9da103e.filesusr.com/ugd/9cb112_7336fbf00a6042f38437b38ee00cefca.pdf?index=trueIn 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://scripts.sil.org/OFLIn 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_off000192c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x192C1 5512 bytes
SHA-256: 0f6d639862a978687fcc379a68a2221561ff79eea07214668a140b67b9c8669d
font_01_sfnt_off0001a57e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1A57E 12860 bytes
SHA-256: 8bf6dbe2c465796cdcd8934fb54df4c345f75ba854ff36f0eebe021e439b8dc6
font_02_sfnt_off0001cfc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1CFC4 16256 bytes
SHA-256: b59b7e27d8cbd76608d9264462d9747125ed6e75e4c0c095c279f9106360cae4