Malicious PDF — malware analysis report

Static analysis result for SHA-256 4145f81c2cd5f55c…

MALICIOUS

PDF

74.3 KB Created: 2021-04-06 21:30:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: dcab3effefbf4f59ab18a1d862fe9ff1 SHA-1: 71ff7fe3c6508aa912f3395d912e292f930a3c14 SHA-256: 4145f81c2cd5f55c476a09cb2512ed86805c5bacbc3f7d86e18d32efe0f25c03
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 of which are structured to appear as SEO-optimized content, suggesting a link farm or content stuffing tactic. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution via these external links. No scripts were extracted, but the PDF structure itself facilitates the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://leonvi.ru/wix?keyword=percent+error+practice+problems+answer+key
    • https://fobinoxibenor.weebly.com/uploads/1/3/1/4/131437242/dutovididire_tipijesavu.pdf
    • https://static.s123-cdn-static.com/uploads/4457311/normal_600346014e0b6.pdf
    • https://cdn-cms.f-static.net/uploads/4385228/normal_6068d40739895.pdf
    • https://kobirozo.weebly.com/uploads/1/3/4/8/134846370/3624828.pdf
    • https://static.s123-cdn-static.com/uploads/4468836/normal_60017901ee295.pdf
    • https://cdn-cms.f-static.net/uploads/4407788/normal_601879aa9f7ac.pdf
    • https://cdn-cms.f-static.net/uploads/4405654/normal_604a53087bb6a.pdf
    • https://cdn-cms.f-static.net/uploads/4365998/normal_6013a4f120b60.pdf
    • https://cdn-cms.f-static.net/uploads/4368768/normal_603d3bd047566.pdf
    • https://kamekupamekom.weebly.com/uploads/1/3/0/8/130813698/4406652.pdf
    • https://seporulakokifo.weebly.com/uploads/1/3/4/5/134590723/022689014.pdf
    • https://cdn-cms.f-static.net/uploads/4489259/normal_602443c80a948.pdf
    • https://jajugodi.weebly.com/uploads/1/3/4/9/134902248/suroruniteweda-niniteb-lowekomexatug.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/c0865d78-fd57-4eb5-a650-62c325c76653/carson_dellosa_answer_key_grade_3.pdf
    • http://mupigedosawi.epizy.com/18253345268.pdf
    • https://uploads.strikinglycdn.com/files/4d1da623-eea8-4982-805d-acff0eef0a08/52168412349.pdf
    • https://uploads.strikinglycdn.com/files/c3444a65-0b85-405e-a2c1-b085c35d9019/lozase.pdf
    • http://dejanubotikepiw.rf.gd/benediction_by_august_alsina_audio.pdf
    • http://pirajog.epizy.com/car_bulb_fitment_guide.pdf
    • https://uploads.strikinglycdn.com/files/323446de-2180-40eb-b4c5-e3ddf20bbe78/what_is_the_theme_of_the_world_is_too_much_with_us_and_how_is_it_developed_in_the_poem.pdf
    • https://uploads.strikinglycdn.com/files/415df1ca-ec68-42c7-80d9-7a0f30ce969d/82796781791.pdf
    • https://uploads.strikinglycdn.com/files/d2dcbfa7-b75a-49ec-b690-60fa520ec978/how_does_kitchenaid_bowl_lift_work.pdf
    • https://uploads.strikinglycdn.com/files/ce692ad0-f54c-4bdf-b177-1d876cc07e6a/fluid_dynamics_physics_lab.pdf
    • https://uploads.strikinglycdn.com/files/bc1b7c04-6e8d-4fc6-8b59-90965a23fe1c/jobivexone.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_off0000e461.bin
88aa73629c165a8430c564eb1eb9225d778ec07d8da4b4218e6a01100f9f2cbf
pdf-font-stream PDF embedded font (sfnt) at offset 0xE461 5476 bytes
font_01_sfnt_off0000f6ff.bin
45231b3dc09f0b0f07a61265aa34444ed2bdefffe0634a7e920a5bd5a2e8a099
pdf-font-stream PDF embedded font (sfnt) at offset 0xF6FF 10804 bytes