Malicious PDF — malware analysis report

Static analysis result for SHA-256 25573e633383c32f…

MALICIOUS

PDF

72.6 KB Created: 2021-04-29 17:27:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d83909ea25ad6900db938c4c2ac2ded6 SHA-1: c0ed5b016b0fa386731efe8b7c75b0cc36c9071f SHA-256: 25573e633383c32f0f3fdc72f002a76c354e4c2c0443ae0d551bf98ae912c2ef
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many hosted on disposable domains, suggesting a link farm designed to redirect users. The heuristic 'PDF_SEO_LINK_FARM' indicates a mass of external PDF links, and the 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' heuristics confirm its malicious nature. While no scripts were explicitly extracted, the presence of embedded URLs and the overall structure point towards a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9828

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
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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/strik?utm_term=gre+test+prep+free+pdf
    • http://luvatok.66ghz.com/no_biggie_informal_meaning.pdf
    • https://vuguzunorofina.weebly.com/uploads/1/3/4/3/134322364/xojenebifereki_vujifenerafetap.pdf
    • https://zepekofudi.weebly.com/uploads/1/3/1/4/131407423/maxefupak_zowiwijuta_fowolenuvufamo.pdf
    • https://buronoveze.weebly.com/uploads/1/3/0/7/130739674/354088.pdf
    • https://vinazova.weebly.com/uploads/1/3/2/6/132695356/592eacff01b.pdf
    • http://trydouche.xyz/zolakutejoluwaluvupibaje0q6js.pdf
    • http://yachts-4-sale.com/pixar_short_films_collection_volumeqh8e9.pdf
    • https://gujibukogise.weebly.com/uploads/1/3/1/3/131380045/ninugura.pdf
    • https://kuvezuwuziteb.weebly.com/uploads/1/3/4/3/134388010/2e23de178.pdf
    • http://counterman.ru/tibia_bestiary_guideehprr.pdf
    • https://fijozemubo.weebly.com/uploads/1/3/4/2/134234573/vivusapuzilojasafuvi.pdf
    • https://mufudenufasos.weebly.com/uploads/1/3/4/4/134492520/rasadesaxur.pdf
    • http://znohist.site/28189227796bxxoe.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/xomudufe/tft_cheat_sheet_patch_9._18.pdf
    • https://s3.amazonaws.com/novipaliwid/31411804239.pdf
    • https://3a00e800-a8eb-44ae-aafc-ae9aecab8e06.filesusr.com/ugd/1715bf_cb2eacfc66ae4a89a2ea50272bc46633.pdf?index=true
    • https://s3.amazonaws.com/zaxawetawupo/what_is_made_of_membranes_that_contain_chlorophyll.pdf
    • https://s3.amazonaws.com/wetevali/65202483351.pdf
    • https://s3.amazonaws.com/xasovewipeje/fisher_paykel_fridge_ratings.pdf
    • https://f72b89be-0fa6-41ee-8162-331329ef78ce.filesusr.com/ugd/95089d_547c585d30bb4fda8b7e4ed8ff028b5f.pdf?index=true
    • http://kokitivem.rf.gd/japeselufenirameru.pdf
    • http://tulinavosubod.rf.gd/lepux.pdf
    • https://23fe9111-5aa3-4288-b7a4-a84c242bb647.filesusr.com/ugd/d35b85_28773574919f4e10a7812cf4646a1b6d.pdf?index=true
    • http://mebexadesojixip.rf.gd/leaflet_bahaya_rokok.pdf
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e956.bin
b6df939946526411ef03a3fa00b16ea3602516078c7c78034a21d4ba2e7ee632		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE956 4824 bytes
font_01_sfnt_off0000f9d3.bin
37fff257f528c485543054ad7d8be383a3e5b811542b335dcf824873038019d8		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF9D3 11116 bytes

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