Malicious PDF — malware analysis report

Static analysis result for SHA-256 0f1a3c0b576b219a…

MALICIOUS

PDF

79.8 KB Created: 2021-03-23 01:42:03 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: cdbb5ed436a169a08d08d421113471d5 SHA-1: d53e44a4e49f08a90956d0c773c891d5388d6105 SHA-256: 0f1a3c0b576b219ad6e2d4a0abca6a7f94eb7e6e57219198f87bf7236e8e6018
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to disposable domains, suggesting a link farm or redirection mechanism. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. The document body, though partially corrupted, suggests a lure related to IELTS reading materials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • 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 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://vilenefex.ru/123?utm_term=ielts+reading+passage+3+with+answers
    • http://antinomi.design/durogomavakanozusuz48d6f.pdf
    • http://basiditdcf.space/amazing_deals_onlinec5d8z.pdf
    • https://nofemifi.weebly.com/uploads/1/3/2/7/132710694/95cd79f5047b.pdf
    • https://static.s123-cdn-static.com/uploads/4470016/normal_5ffa91e098b3e.pdf
    • https://ledijonag.weebly.com/uploads/1/3/4/6/134689342/ramame.pdf
    • http://srakan.space/fesogomupasiayl5d.pdf
    • http://fimewot.xyz/answers_of_chapter_combustion_and_flamehe7q6.pdf
    • https://cdn-cms.f-static.net/uploads/4425728/normal_602d7f5134a56.pdf
    • http://fruitslope.online/will_verizon_iphone_work_with_straight_talkcfkni.pdf
    • https://cdn-cms.f-static.net/uploads/4487386/normal_603b96ed0ff83.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://4a7d9d2b-1d67-446c-8d6d-bdd3043d1f60.filesusr.com/ugd/c3d078_f46ac09a390147c9adf829514aa18526.pdf?index=true
    • https://uploads.strikinglycdn.com/files/785355df-c35e-4eae-8c69-10469366f391/25221826875.pdf
    • https://uploads.strikinglycdn.com/files/4043a9d9-3921-4b49-8f70-c0c5dc137812/saxagavav.pdf
    • https://71bfc0c6-4bef-405a-aee6-9e9dcaab3d12.filesusr.com/ugd/708cfd_c1c6b3daddd542b88ef3c5cc91efb6cb.pdf?index=true
    • https://989244f3-426d-4557-b4f1-0018dac9047c.filesusr.com/ugd/57c819_6ec6f525d5234eef87fc4285a07ea91c.pdf?index=true
    • https://uploads.strikinglycdn.com/files/cdb0091e-0a75-4a21-9f08-5d1741607028/90589551611.pdf
    • https://c0add167-8731-41f0-9a7b-3d62f09b0499.filesusr.com/ugd/879476_1fc68d4fe00c4295a58f8826782ad421.pdf?index=true
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f930.bin
cc672a2e66845b3dc8e2f87c444ca05e04ea77380407839a28e1ab008ea7e305		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF930 5416 bytes
font_01_sfnt_off00010ba3.bin
b0a0a8a9c721d973b637e3224e185d73bc5bcd1c47567b5f9e54914bcf756586		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10BA3 11376 bytes

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