Malicious PDF — malware analysis report

Static analysis result for SHA-256 8536cf60635ee80f…

MALICIOUS

PDF

72.0 KB Created: 2021-05-30 13:42:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 015451cc7ba0e5124597f03f3896d405 SHA-1: 6bcb5dc2db9ba4f7323ec2d8475b134998d9d628 SHA-256: 8536cf60635ee80f95f6baced2696800fdcfc74015ecca4838982f790f7a7e11
244 Risk Score

Malware Insights

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

This PDF file contains a large number of links, many of which point to disposable hosting services and redirectors, indicating a link farm designed to manipulate search engine results. The primary redirector URL is 'https://dafemum.ru/strik?utm_term=ejercicios+de+probabilidad+universidad+resueltos+pdf', which is likely part of a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly support its 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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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.
  • 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://dafemum.ru/strik?utm_term=ejercicios+de+probabilidad+universidad+resueltos+pdf In PDF document text
    • https://xipixipoduk.weebly.com/uploads/1/3/7/5/137501676/josupapelafus_degezofajix_lizevukur.pdfIn PDF document text
    • https://nusomosuguxapo.weebly.com/uploads/1/3/4/6/134693055/ffa8bcb90.pdfIn PDF document text
    • https://wifirinopemuv.weebly.com/uploads/1/3/4/7/134762260/resetot-jirinumisexugu.pdfIn PDF document text
    • https://fosisires.weebly.com/uploads/1/3/4/5/134522908/gekeda.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4410702/normal_60421f59acab8.pdfIn PDF document text
    • https://dapobatajixafaw.weebly.com/uploads/1/3/4/3/134310280/mizusuk.pdfIn PDF document text
    • https://momekefu.weebly.com/uploads/1/3/4/8/134850451/4414926.pdfIn PDF document text
    • https://jijubukaxujofi.weebly.com/uploads/1/3/4/8/134892288/386888.pdfIn PDF document text
    • https://zavuvomexuwu.weebly.com/uploads/1/3/2/7/132740545/sobabenezor_fevezopel_kimugusunivex_wegisi.pdfIn PDF document text
    • https://zetapowopes.weebly.com/uploads/1/3/0/8/130813904/kafetebe.pdfIn PDF document text
    • https://gepepokomireke.weebly.com/uploads/1/3/4/8/134892048/xalodexuwug_regutamus_xufosomixav.pdfIn PDF document text
    • https://rutobugexamaxip.weebly.com/uploads/1/3/4/5/134508198/jujaxitesaviwo_wezubolip.pdfIn PDF document text
    • https://dupivujo.weebly.com/uploads/1/3/4/6/134612497/wabavasodapepiwizo.pdfIn PDF document text
    • https://ralakugifobiw.weebly.com/uploads/1/3/4/5/134589758/bowotatiwugi.pdfIn PDF document text
    • https://nowefatitabawev.weebly.com/uploads/1/3/2/7/132740181/17072bc3d4fb89.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4471706/normal_605977d5e6eac.pdfIn PDF document text
    • https://topitodowel.weebly.com/uploads/1/3/4/8/134890479/cc12c69b3.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/d1e4c972-22f8-4413-8339-e028347d1737/89751553751.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/dfca64b7-d5df-406d-b1ae-bd6705443ff4/22279086095.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f3b0f594-f7c4-4c96-a244-c8f01cba6b5f/xagixezeneronuvilego.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b4ac73f4-5af7-4c36-9199-339352dfc460/three_stages_of_career_development_meme.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_off0000d964.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD964 5380 bytes
SHA-256: f6a4d2b531dc8f35ee7ec8a9968e5bae3003535759d042f7910ebe9474805e26
font_01_sfnt_off0000ebc8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBC8 11012 bytes
SHA-256: 77bf724120de15afef72ac4427ec75b5deba8761384eb7740e8272d6ff22427e