Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d4b7ed3a141eff7…

MALICIOUS

PDF

81.7 KB Created: 2021-04-02 16:28:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: d8ce14311095655096ad02a805e24738 SHA-1: 8d5eb6a8af315b356b759b9622a4c1f00db8ccfd SHA-256: 8d4b7ed3a141eff7f36b2e7c3ba19f7d6f4a1b93071a0cc881befbe1dd924a10
186 Risk Score

Malware Insights

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

This PDF file is identified as malicious by multiple heuristics and an ML classifier, and is detected by ClamAV as Pdf.Phishing.Trojan. It contains a link farm with numerous external URLs, including one that appears to be a lure for educational materials. The presence of embedded URLs and the nature of the link farm suggest an attempt to redirect users to malicious sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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
  • 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://nipisod.ru/award?keyword=adjetivos+possessivos+em+ingles+exercicios+6+ano+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4416322/normal_602a09be19b76.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4423462/normal_5feb494268fa1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4485445/normal_5fd7b14557d3c.pdfIn PDF document text
    • https://cdn.sqhk.co/vobevufubito/igjiija/63688318109.pdfIn PDF document text
    • https://cdn.sqhk.co/fakobijo/0hgjavs/1807334126.pdfIn PDF document text
    • https://cdn.sqhk.co/wazofovam/haAzTCt/blockchain_technology_applications_in_power_distribution_systems.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4375080/normal_5fdf7ad829122.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4382781/normal_602fc593bff6f.pdfIn PDF document text
    • https://cdn.sqhk.co/zimuteraf/pgiZ4Ut/30950402101.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://f4ef19d8-372f-49db-bbb6-0f5e16bfa625.filesusr.com/ugd/070799_3cae67c2ce90462b9318061f79e66e05.pdf?index=trueIn PDF document text
    • https://48bd7725-9370-4d18-884e-e75d7b70c9c4.filesusr.com/ugd/f241d9_85b969669b7140ae9bac3643f37d1d26.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/c3bbe67d-1716-476c-8785-fe41ef6882d0/lulikozobezenanilosorigox.pdfIn PDF document text
    • https://f7cac2f2-528f-490f-9bef-cb2448a877de.filesusr.com/ugd/529ba0_92e7ac7a9d5f4a3fbe0e7c244bb99075.pdf?index=trueIn PDF document text
    • https://9df6e0af-a028-4e88-91ba-61a1b37318d5.filesusr.com/ugd/7c1f05_b6c09c039a22441aa6de343d0ddeffaa.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/9c7870e9-ace0-472f-ad63-db25f7506a6e/3796904637.pdfIn PDF document text
    • https://e8b83640-91e4-44a0-a69f-c2468797902f.filesusr.com/ugd/ee4a13_fda6b38e338f45acb22edf2c5aa56502.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/10dfdce7-4892-4228-9be6-6d2db4b4feef/23487713008.pdfIn PDF document text
    • https://436240a4-ef10-404e-ad90-c5cab949c7af.filesusr.com/ugd/3fb742_3b297da27e594e1db4e035fd351c2372.pdf?index=trueIn PDF document text
    • https://d2d87fd5-5f4d-49aa-ab3c-2263ce4b5d22.filesusr.com/ugd/9169d2_5819959e0ca74754904199e71470bc81.pdf?index=trueIn PDF document text
    • https://fb1cd387-549b-40f1-a5a4-67fd65d29bb3.filesusr.com/ugd/4200b4_7dedb611dca540158b44fa258d4e4af3.pdf?index=trueIn PDF document text
    • https://73f4d879-981c-49fe-abc7-520f36a14a84.filesusr.com/ugd/b77b08_f3aad7a09adc4a75a5dffe6698553772.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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fc38.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC38 5824 bytes
SHA-256: 75c6bcc13df291e757eaac10d4f7754babccd9b50ebe8288dcd676d02d9b4a5a
font_01_sfnt_off0001100b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1100B 12620 bytes
SHA-256: 75c5086a847cc751a2ebcf6ae5b84b0cabf959d929ecaf2bca8ea6604aa0720c