Malicious PDF — malware analysis report

Static analysis result for SHA-256 af31a4cae6cc428d…

MALICIOUS

PDF

79.3 KB Created: 2021-05-01 02:06:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: 1e3e8895f74e91f48cf0bc97f0f3d050 SHA-1: c9f7761bdef823cd646f0ed3cace6f127b8d4756 SHA-256: af31a4cae6cc428d34e4c29557e4044903201d1468458a0b025a77f2d5c57347
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of embedded links, many pointing to disposable hosting or known malicious redirectors. The ML classifier and ClamAV heuristics strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and appears to be junk data, but the presence of numerous external links is the primary indicator of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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=maui+revealed+the+ultimate+guidebook+9th+edition In PDF document text
    • http://genoray.pro/solid_state_physics_ashcroft_solution_manualuzn76.pdfIn PDF document text
    • https://jowopuvuramikir.weebly.com/uploads/1/3/5/3/135313070/b9d431e.pdfIn PDF document text
    • https://bijadatexate.weebly.com/uploads/1/3/4/0/134013249/5266957.pdfIn PDF document text
    • http://pojapusevipuzu.mypressonline.com/smartphone_addiction_definition.pdfIn PDF document text
    • https://nujalujuxak.weebly.com/uploads/1/3/5/3/135347358/65269e65f1.pdfIn PDF document text
    • http://rumigiwataj.getenjoyment.net/classification_des_bryophytes.pdfIn PDF document text
    • https://cdn.sqhk.co/tavaxiwugo/jihebhf/42671767849.pdfIn PDF document text
    • http://drive4mclaneeffingham.com/dubai_tourist_map_2018kk1m4.pdfIn PDF document text
    • https://wabibazo.weebly.com/uploads/1/3/5/2/135295983/morepolap-pujadasapugis-badawafereboweb-binasakuju.pdfIn PDF document text
    • https://cdn.sqhk.co/zerurukoraju/fVvhbge/pc_building_simulator_free_2020.pdfIn PDF document text
    • http://shopwithsale.website/bently_nevada_3300_xl_wiring_diagram5yyj2.pdfIn PDF document text
    • https://cdn.sqhk.co/jegamaxegev/XiejTgj/esl_past_simple_passive_worksheets.pdfIn PDF document text
    • https://fojaloda.weebly.com/uploads/1/3/0/7/130776233/85b80dcc.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://f039f7e9-c7fa-441d-bf3d-2f0e35d6be10.filesusr.com/ugd/80685d_9e57155b9e554657bc58091340e52536.pdf?index=trueIn PDF document text
    • https://af30af13-e0b7-4de0-aca7-7783c01eade2.filesusr.com/ugd/9757e7_19c1322f26804e26b8e85bacf55fcd64.pdf?index=trueIn PDF document text
    • https://91506351-5699-48ce-85e7-8e7d071f4e87.filesusr.com/ugd/d775a9_2a06576475a240d5b07d70e0e2cd171c.pdf?index=trueIn PDF document text
    • https://f733e552-90a1-4d1f-83ca-a6b36afcf31c.filesusr.com/ugd/38bf1f_4c0f3c106bde4eab99762a70a3ff1998.pdf?index=trueIn PDF document text
    • https://6f84c080-6bd2-4154-8ce1-0e390380bda5.filesusr.com/ugd/defdb4_0b1ea75eb479461e908568f5e3424c36.pdf?index=trueIn PDF document text
    • https://51956041-da35-40aa-96c1-085c1f47c80d.filesusr.com/ugd/e6e573_f9ff99410bbf47b3b1e2357d560979a3.pdf?index=trueIn PDF document text
    • https://34e2f0dc-0077-42bd-a047-efa2502e92af.filesusr.com/ugd/8a05ec_ef6a1d596dad4ebe85981b960664d19e.pdf?index=trueIn 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_off0000f98c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF98C 5484 bytes
SHA-256: a9584dd8ea8cbfc6517cd1321061ad17c58fe95c1986314b8ffbcf1cc31654c8
font_01_sfnt_off00010c15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C15 10928 bytes
SHA-256: 8ffbd91191a3fdff4475dd8e7e607292481fd4d67cd9b6f068df9bf4a8eea2b6