Malicious PDF — malware analysis report

Static analysis result for SHA-256 f81aa2865c538cee…

MALICIOUS

PDF

71.4 KB Created: 2021-01-25 02:36:04 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 1ce0772e6213bd2fbbf2b7768b9d63ab SHA-1: 7f9774dc9507454238214f806cb6ad83993abca9 SHA-256: f81aa2865c538cee478022f503ffc916ff709e0002d22e146aee202d8d1c233a
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file contains numerous external links, identified as a link farm, with a high ML classifier score and ClamAV detection indicating malicious intent. The document body, though heavily obfuscated, suggests a lure related to 'The last leaf poem' and uses wkhtmltopdf, indicating it's likely a generated document. The presence of external URIs and the link farm heuristic strongly suggest this PDF is designed to redirect users to potentially malicious websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://maypoin.ru/123?utm_term=the+last+leaf+poem PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4471704/normal_600385dee116d.pdfIn PDF document text
    • http://0fruits.space/temple_run_2_lost_jungle_game_playg85te.pdfIn PDF document text
    • https://jobifavizatop.weebly.com/uploads/1/3/4/1/134108852/9370600.pdfIn PDF document text
    • https://migerele.weebly.com/uploads/1/3/1/4/131453560/39488afb66a35fd.pdfIn PDF document text
    • https://galujamisone.weebly.com/uploads/1/3/1/8/131871568/mewevonogamogokig.pdfIn PDF document text
    • https://rokumipizo.weebly.com/uploads/1/3/0/7/130776068/f44a96ec9a.pdfIn PDF document text
    • http://specrazreshenie.com/liniji56hrm.pdfIn PDF document text
    • http://italiahot.fun/noparananifupej12op.pdfIn PDF document text
    • http://fullhp.info/space_rangers_earth_37rc2um.pdfIn PDF document text
    • https://nemelodanunoju.weebly.com/uploads/1/3/0/8/130874480/64fd013.pdfIn PDF document text
    • https://cdn.sqhk.co/gukugifixija/HkKhihb/julokegiriboresovaverov.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446491/normal_60014ca5287af.pdfIn PDF document text
    • https://venubitolaxi.weebly.com/uploads/1/3/4/3/134372432/1985457.pdfIn PDF document text
    • http://avto-trokot.xyz/family_feud_live_play_with_friendsgakac.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4383446/normal_6003dbda24656.pdfIn PDF document text
    • https://cdn.sqhk.co/tumowara/iaGgdJD/91306307299.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4419195/normal_5fc78e07b5bef.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://nanabiwilave.epizy.com/cobit_2019_design_guide_free.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dbb9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBB9 4992 bytes
SHA-256: 5cfcf0a44433476c018da43106f6a18f8c5c5950250c745c26c0bca5a8844118
font_01_sfnt_off0000ec91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC91 10836 bytes
SHA-256: 24bbf64db7317821bb2f04d6bbd9dd46d3605254748f54b7f093983f038394b4

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