Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a5b735776ebfd6f…

MALICIOUS

PDF

75.3 KB Created: 2021-02-14 05:41:34 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-17
MD5: a4fbab4e717e04fd8d78bd56040dc401 SHA-1: 56f63d80bcbdf3a3501f4387beec0b9fbba50831 SHA-256: 8a5b735776ebfd6f24ca4c27b918eb5e59ee171664c1c9d2749444630f83c30d
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of embedded links, many of which point to disposable hosting and redirectors, indicating a link farm designed to distribute malicious content. The heuristic 'PDF_MALICIOUS_REDIRECTOR_LINK' specifically flags a URL leading to known malicious infrastructure. The ML classifier and ClamAV detection strongly support the malicious nature of this file.

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://yafferge.ru/wix?keyword=upenn+early+decision+2020 In PDF document text
    • https://cdn-cms.f-static.net/uploads/4420244/normal_5fd7f83d66ecd.pdfIn PDF document text
    • https://cdn.sqhk.co/povewepalu/1JMxiCa/ittf_table_tennis_score_sheet.pdfIn PDF document text
    • https://vamarimorojikav.weebly.com/uploads/1/3/4/6/134640123/5505897.pdfIn PDF document text
    • http://aycotoro0.xyz/plexos_nerviosos_del_cuerpo_humano1mewb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415052/normal_6017dc97c53aa.pdfIn PDF document text
    • https://cdn.sqhk.co/farafakilof/ckgdbe7/80151732240.pdfIn PDF document text
    • http://befelofote.iblogger.org/aphasia_therapy_materials.pdfIn PDF document text
    • https://cdn.sqhk.co/vulovosovem/ajaSjbC/escape_plan_3_release_date_netflix.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4426971/normal_5ff05dda36b5a.pdfIn PDF document text
    • http://lnstagram-help-businesss.com/49453002049v0kvi.pdfIn PDF document text
    • https://cdn.sqhk.co/kolokejo/hbvk8yq/face_changing_skyrim.pdfIn PDF document text
    • http://edalovert.xyz/81498695022embst.pdfIn PDF document text
    • http://form-copyrightservices.com/zatatesakenebgli6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4475406/normal_600ae389f1aee.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://tirujukixiw.epizy.com/sokowajufufukasumetakam.pdfIn PDF document text
    • http://muwojes.epizy.com/susozaninaro.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_off0000e961.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE961 5436 bytes
SHA-256: b3fffc490204719d0e21b833d3634e1bc8370385ef5d1ae6d21317bdb0ff7381
font_01_sfnt_off0000fbf4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBF4 10652 bytes
SHA-256: d1f6623adb5be34598719cfe1897dfd208d151a77a79e0cf1b977b49f2270f86

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