Malicious PDF — malware analysis report

Static analysis result for SHA-256 51b0648ce6614753…

MALICIOUS

PDF

77.2 KB Created: 2021-05-28 20:54:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: 66e24bb15f45107451995f81300493ca SHA-1: de4cb2f5de787c845ae35d9319924989f0286253 SHA-256: 51b0648ce6614753284bb650d5d02fd37b6b64a9f1142bd6e2cdb035078aded9
244 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded links, many of which point to disposable hosting or known malicious redirectors. The primary malicious URL identified is 'https://crophysi.ru/strik?utm_term=cloud+games+mod+apk+rexdl', which is likely used to deliver a phishing or malware payload. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://crophysi.ru/strik?utm_term=cloud+games+mod+apk+rexdl In PDF document text
    • https://cdn-cms.f-static.net/uploads/4444869/normal_602ffc1956ae2.pdfIn PDF document text
    • https://taxurazuzar.weebly.com/uploads/1/3/4/0/134042721/4422550.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4420018/normal_5fec7cd00309e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4476765/normal_5fd78c9b5f40d.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470533/normal_6040b4d003717.pdfIn PDF document text
    • https://juwabizaf.weebly.com/uploads/1/3/0/9/130969053/vodedikiferojukogi.pdfIn PDF document text
    • https://bikojeril.weebly.com/uploads/1/3/3/9/133999271/9983867.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4387243/normal_6019331e33897.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417669/normal_603d1bb9dfa40.pdfIn PDF document text
    • https://rapozudomemixu.weebly.com/uploads/1/3/5/3/135330029/4512447.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4489976/normal_5fc6a6d76eef8.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4426271/normal_601f0e1c459b6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416929/normal_6054db0bb3ee7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4418747/normal_600c6fe0b6f1d.pdfIn PDF document text
    • https://static.s123-cdn-static-d.com/uploads/4382193/normal_60b05cee5fad8.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/f2054f64-d692-4e38-ac1a-b1b8e9e5ff9e/an_attributional_theory_of_achievement_motivation_and_emotion.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/289666fe-5c5d-445f-bd45-d86015a96219/which_is_the_best_ice_cream_maker_to_buy.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/42d6791a-0472-4efc-b91a-a695273db3e1/the_meaning_of_marriage_tim_keller.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/98b5377c-9e74-47e4-aed7-1524e505a5b9/traductor_espaol_e_ingles_audio.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6751b8ee-f0ff-4d9d-9d78-6cd1e5df04b1/wubovom.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_off0000efa5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFA5 5316 bytes
SHA-256: db5eee3aa6fb4522e6a40904cb8f28270441a755cfa0507b779252fc53f35318
font_01_sfnt_off000101a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101A4 11160 bytes
SHA-256: e727168812c250120cdb974349e46e8dee18ea7d60b8e31f133597c8c0f91c47