Malicious PDF — malware analysis report

Static analysis result for SHA-256 aca5cff91455cdba…

MALICIOUS

PDF

76.3 KB Created: 2021-05-26 04:00:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: ed6f1cfc6da7cfc9cc1b85634b5c8f75 SHA-1: 226a1dac0e9049e30aec20441efd8aba801e648e SHA-256: aca5cff91455cdbae8a78633b001958b4404ed1bfda6dc056cd2a5e65eb9b0b2
196 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which point to SEO-optimized PDF files, suggesting a link farm or phishing lure. The primary malicious URL, 'https://leonvi.ru/strik?utm_term=noun+phrases+worksheets+for+grade+3', is identified as an SEO redirector for phishing. ClamAV also detected the file as 'Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0', reinforcing the phishing and malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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/strik?utm_term=noun+phrases+worksheets+for+grade+3 PDF link annotation
    • https://memezuwiz.weebly.com/uploads/1/3/4/7/134702577/kesuzovigonem.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379489/normal_605c99da59bf4.pdfIn PDF document text
    • https://jatekowi.weebly.com/uploads/1/3/0/7/130776123/gowike_toliwuxeruv_kovaxujezibuma_joven.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369654/normal_5fd3215279c2d.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/baposivarabuj/avast_mobile_security_premium_apk_free.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/74b430eb-a13e-40bc-b823-4b301b20a67e/lg_front_load_washing_machine_will_not_drain.pdfIn PDF document text
    • https://s3.amazonaws.com/wulagisi/nafilipegevudif.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6531705e-2e2b-42d8-a29f-7a6a0d8a75bb/25580757564.pdfIn PDF document text
    • https://s3.amazonaws.com/mujesogi/subject_verb_agreement_exercise_4_answer_key.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3dc0f33e-211c-4dfe-87ff-353647519b4d/pirizovota.pdfIn PDF document text
    • https://s3.amazonaws.com/falevi/work_review_answers.pdfIn PDF document text
    • https://s3.amazonaws.com/dazutun/71387424328.pdfIn PDF document text
    • https://s3.amazonaws.com/padanivozeb/forgotten_fire_adam_bagdasarian.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/93cdfe76-b004-46f0-acb8-30b861acc8c9/33829389813.pdfIn PDF document text
    • https://s3.amazonaws.com/gulapore/30591977224.pdfIn PDF document text
    • https://s3.amazonaws.com/widuxade/49562523239.pdfIn PDF document text
    • https://s3.amazonaws.com/saziwijaxodav/ge_spectra_oven_manual_calibration.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/756f4a1c-b386-4f4f-8dfc-813b3850529b/linux_system_programming_oreilly_download.pdfIn PDF document text
    • https://s3.amazonaws.com/pojikovewijeja/kudubatewimuxusuve.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b891e917-c016-4ef5-ac85-76393b3938c9/what_do_black_ants_mean_in_a_dream.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/dc2c8982-73e4-43c4-a5ef-fbe45c20a804/5614874059.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_off0000ea32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA32 5560 bytes
SHA-256: c3cd5f5d6a1b70f4dfc82219f3143162b60f548c8ce25ca72e6e1697ed1d1155
font_01_sfnt_off0000fd30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD30 11260 bytes
SHA-256: db77ea3fd3631dedae77177ab0615f9300081396b60121663104852efc8c1da2