Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbf73381126e2ff9…

MALICIOUS

PDF

78.9 KB Created: 2021-03-16 01:39:35 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 5048d2f53437878464c8b9265f6c3cdc SHA-1: 9c61fe7c79fad394617ad26a95b12f18b4069661 SHA-256: cbf73381126e2ff9c1041b565ee5a58314968b34548643356903f215012f5360
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains a large number of external links, identified as a 'PDF_SEO_LINK_FARM' heuristic, suggesting a tactic to manipulate search engine results or redirect users to malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or trojan delivery. The document body, though heavily obfuscated, references 'autism spectrum disorder checklist pdf', indicating a lure to entice users to click on the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://bologen.ru/award?keyword=autism+spectrum+disorder+checklist+pdf
    • http://ruroraratotu.66ghz.com/gender_ideas_interactions_institutions_2nd_edition_free.pdf
    • http://fefebigaxef.iblogger.org/14227351752.pdf
    • http://medesutaduj.22web.org/how_often_to_change_filter_on_hot_tub.pdf
    • https://cdn.sqhk.co/lepavenujal/hczGMhf/natural_background_images_hd_1080p_free.pdf
    • https://cdn.sqhk.co/gabisolovima/hftNhgO/pandemic_unemployment_assistance_california_for_self_employed.pdf
    • https://sowofodifidem.weebly.com/uploads/1/3/1/8/131856479/2157355.pdf
    • https://cdn.sqhk.co/metexemoraga/SBDja5h/adventure_story_2_all_bosses.pdf
    • https://wixotofipexux.weebly.com/uploads/1/3/5/4/135400714/dc57cf45585.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://5563968e-3cf5-463b-8312-7915ab8a4794.filesusr.com/ugd/cd90d1_6ad11f5ddfc1441fa5eb936d88fa497e.pdf?index=true
    • https://b81e1767-bb0d-4562-9f98-cfef66859bb1.filesusr.com/ugd/b48b60_3f42ce0c49024e5ba6f7d67f7343fd32.pdf?index=true
    • http://dawutanarav.epizy.com/sandisk_clip_sport_plus_not_turning_on.pdf
    • https://uploads.strikinglycdn.com/files/c58d43d9-895d-4441-a6eb-9642eaa2df0d/california_rental_lease_agreement.pdf
    • http://waxozex.epizy.com/957141486.pdf
    • http://rifovedukuj.epizy.com/60362841870.pdf
    • https://625f08e2-3d8e-45b5-8e8c-b95d001c5c7c.filesusr.com/ugd/d94ae5_bd26d63d2576410da685e5782a2734c4.pdf?index=true
    • https://3228dc58-b2c1-4aed-ac20-03fc52793822.filesusr.com/ugd/43afbb_53ef1a74c84c4075840ee0073cbe9539.pdf?index=true
    • https://uploads.strikinglycdn.com/files/a45fa1d2-986c-4933-a419-ecb5e48a16b8/what_is_a_global_management_consulting_firm.pdf
    • http://buwobazakosujo.rf.gd/7108738425.pdf
    • https://uploads.strikinglycdn.com/files/d78ce6c5-0baa-42fb-a599-9d834a7d89be/kerajeteledejapafefafonaw.pdf
    • https://6e229dea-1f83-4be8-8cd3-388eabd4f5e3.filesusr.com/ugd/1cfe37_6b1a231688744134a05ec692d7983027.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_off0000f883.bin
ff239032615e80dbee6783be1be8d951eaa322d1b2225217bda8ac9462c72c6c		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF883 5240 bytes
font_01_sfnt_off00010a2d.bin
64d2a920559586667deef87da997c4f6ff8b0f7cc7720a701966d807386e73d8		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10A2D 10652 bytes

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