Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b11bed4899161c…

MALICIOUS

PDF

116.2 KB Created: 2021-03-06 07:28:20 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: b16f5d4b3d9550385d0ba01f53ec23ff SHA-1: 2620b9af801ff3e24edbdd6c67bbd9cdedf55388 SHA-256: 81b11bed4899161c5fd5de65142601e9bd537de4037f94fb796bd8dfa030828a
134 Risk Score

Malware Insights

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

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many of which point to disposable domains and appear to be part of a link farm, suggesting a phishing or malware distribution campaign. The document body, though heavily obfuscated, contains keywords related to politics and a tool name (wkhtmltopdf), indicating it's likely a lure. The presence of external URIs and the overall structure strongly suggest an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://baarspo.ru/wix?keyword=winner+take+all+politics+pdf PDF link annotation
    • http://my-favshop.online/puvekasuzotu84e4u.pdfIn PDF document text
    • http://newsportstechnology.ru/kindle_paperwhite_instructions_for_dummiesfw6t4.pdfIn PDF document text
    • http://airet.space/55760064522do4ju.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423133/normal_5fd656fd39b03.pdfIn PDF document text
    • http://dewisazovuvoxi.mywebcommunity.org/5958840913.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4402517/normal_5ffa8732a6e72.pdfIn PDF document text
    • http://pokemonrivals.online/85726465771o5qaz.pdfIn PDF document text
    • http://6gusevshop.space/integrated_science_course_3_answersdr3sl.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4418755/normal_5fcd2e65b05ea.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4450638/normal_5fdd817884b42.pdfIn PDF document text
    • http://bopugafuwu.scienceontheweb.net/whats_good_to_mix_with_crown_royal_salted_caramel.pdfIn PDF document text
    • http://bikejesoxatelo.mygamesonline.org/9230960961.pdfIn PDF document text
    • http://nout-prodat.site/elastisite_teorisi_snav_sorularii6ow.pdfIn PDF document text
    • http://kavademive.sportsontheweb.net/greek_mythology_novels_for_middle_school.pdfIn PDF document text
    • http://mx50off.info/gasikibalobofupakugetipokp2e3.pdfIn PDF document text
    • http://rezisekuvaz.mypressonline.com/distribucion_normal_estandarizada.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4461205/normal_5fc810e66c0d1.pdfIn PDF document text
    • http://xenalebosob.scienceontheweb.net/machine_learning_models_for_classification_of_bgp_anomalies.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://bitenozof.atwebpages.com/nupanusunavavulozanerix.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a9747127-445b-436e-8d8f-68aa1d2ff707/88613339508.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8b75b21e-460f-400a-922c-d925ee5e32b8/how_much_does_a_school_counselor_make_uk.pdfIn PDF document text
    • http://mukanebesiva.atwebpages.com/13001192774.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9a523524-506a-4a24-afd6-9774769147cd/jesazifodejamowa.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_off00018b77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18B77 5224 bytes
SHA-256: 1571bd5646ca233cc850fce33ae44950e8b40f1d86cb61bad0f44c5936ea19b0
font_01_sfnt_off00019d60.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19D60 11040 bytes
SHA-256: 1080bc1a3ef49100a7a1f7437cdb7ad189847b192f2247056b90e32a8b702570