Malicious PDF — malware analysis report

Static analysis result for SHA-256 c2c8439527dc3725…

MALICIOUS

PDF

85.5 KB Created: 2021-05-21 12:24:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 58acb1206a9c102b18e8ebb7f387e05a SHA-1: 7d3fab28baf71b975258b454c89e00210ab4bba3 SHA-256: c2c8439527dc372581d8219e80ca05db5daa605060720e3a162d8e26db7c335d
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to S3 buckets and Weebly domains, suggesting a link farm or SEO poisoning tactic. One of the primary URLs, https://kuzutuzo.ru/strik, is flagged as unknown but is likely malicious given the overall context and ClamAV detection. The ML classifier and ClamAV strongly indicate malicious intent, likely phishing or malware distribution via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • 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
  • 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://kuzutuzo.ru/strik?utm_term=quanto+pesa+un+metro+cubo+di+aqua
    • https://wilowukodol.weebly.com/uploads/1/3/4/8/134881933/1588758.pdf
    • https://cdn-cms.f-static.net/uploads/4463830/normal_5fd67e1a64cc1.pdf
    • https://kekisuganuzab.weebly.com/uploads/1/3/4/7/134721312/85865cdd5ee0e7.pdf
    • https://tobisimotar.weebly.com/uploads/1/3/5/3/135330661/ed68928d98187cd.pdf
    • https://dudixojazimonam.weebly.com/uploads/1/3/4/6/134638097/dovaruxopoto.pdf
    • https://voximarabot.weebly.com/uploads/1/3/1/3/131383255/gitidopixe.pdf
    • https://cdn-cms.f-static.net/uploads/4390055/normal_6045c4bb32192.pdf
    • https://cdn-cms.f-static.net/uploads/4381971/normal_5fd3236b93365.pdf
    • https://xowanejizaki.weebly.com/uploads/1/3/1/8/131871556/pamefadi_kiduniwemozuw_voluwaguwi_dozuwolupajeri.pdf
    • https://tavutafaj.weebly.com/uploads/1/3/1/4/131482866/12b3af59af444.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/gajakelegeza/jaradunemulobubibuguzuf.pdf
    • https://s3.amazonaws.com/vuzotisenixava/nonlinear_ordinary_differential_equations_problems_and_solutions.pdf
    • https://s3.amazonaws.com/vuraradaso/baby_one_more_time_lyrics.pdf
    • https://s3.amazonaws.com/mavixu/standardized_test_practice_answers.pdf
    • https://s3.amazonaws.com/xugigabitulu/what_is_united_colors_of_benetton.pdf
    • https://s3.amazonaws.com/tezude/ludiramopegobi.pdf
    • https://s3.amazonaws.com/bubodeliza/mariam_khan_reporting_live_star_plus_cast.pdf
    • https://s3.amazonaws.com/vofadoloves/anexos_del_aparato_digestivo.pdf
    • https://uploads.strikinglycdn.com/files/36f7521e-bf02-42aa-9b53-bbd76e013f36/in_cost-plus_pricing_the_target_selling_price_is_computed_as.pdf
    • https://s3.amazonaws.com/silubebebefuju/ribuwoxalunaxexijoteza.pdf
    • https://uploads.strikinglycdn.com/files/09e92d6f-ccde-4992-bd01-6a68677940e6/how_much_was_gold_worth_in_1985.pdf
    • https://s3.amazonaws.com/loranoduzuja/amma_amma_music_ringtone.pdf
    • 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_off00010b5a.bin
550778e316dcbbc5a0bf8b60cc12092f61c59d2835298ae26418708212dfe6f8
pdf-font-stream PDF embedded font (sfnt) at offset 0x10B5A 5512 bytes
font_01_sfnt_off00011dee.bin
41c6ddb114658373dcbbe348080c768c7b57449c2185787bac69341bc752cf85
pdf-font-stream PDF embedded font (sfnt) at offset 0x11DEE 12752 bytes