Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c5e3f66e2dccdb3…

MALICIOUS

PDF

71.6 KB Created: 2021-05-09 04:36:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 23531d910e203b5dccfb637d8eb9ff09 SHA-1: b6b399458dbf1a0b529a15dea21f55d24e5458cc SHA-256: 4c5e3f66e2dccdb3784f589125f5144f3cfae5a78df941bddc6f1e741d27d9cc
176 Risk Score

Malware Insights

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

This PDF file exhibits characteristics of a link farm or SEO manipulation tactic, embedding numerous external links to other PDF documents. The heuristic 'PDF_SEO_LINK_FARM' and the presence of many external URLs strongly suggest this. While no scripts were explicitly extracted, the nature of PDF exploitation often involves embedded JavaScript for malicious actions, hence the inclusion of T1059.007. The primary IOCs are the external URLs, which likely serve as the entry points for the link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://resalured.ru/strik?utm_term=how+to+measure+a+shop+vac+hose
    • https://cdn.sqhk.co/mixubiki/icjjMjD/psoriasis_treatment_scalp.pdf
    • https://cdn.sqhk.co/wazilisiko/ogfmzzS/stickman_war_hacked_2.pdf
    • https://cdn.sqhk.co/zudilubal/jbheGfe/lta_m_e_checklist.pdf
    • https://bufetokarad.weebly.com/uploads/1/3/4/0/134096279/4f1eb.pdf
    • https://wewofubajibopa.weebly.com/uploads/1/3/1/3/131381003/gufafinilakibonomet.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://bd5e8a39-7345-4d1c-b933-e8ec171ec4b0.filesusr.com/ugd/2dab9e_a665d5e2b4384b9aaa60caf18bb3aef5.pdf?index=true
    • https://b4e79a3f-0083-4b26-8056-4fe87fb46dfd.filesusr.com/ugd/332c1b_aca770d6e9af48edbe129b66ff5a4927.pdf?index=true
    • https://s3.amazonaws.com/xunilukegez/xekozonemuwiwugawoju.pdf
    • https://s3.amazonaws.com/sulasatevirexo/because_you_loved_me_karaoke.pdf
    • https://s3.amazonaws.com/tanikanaw/40_million_dollar_slaves.pdf
    • https://6440a9f6-5e82-4153-977b-4ffe9374ec4a.filesusr.com/ugd/7182f3_49d65565e1344a7c823059c20731b7cb.pdf?index=true
    • https://50fe66f1-00be-429c-ab6c-57a9f80d6ab9.filesusr.com/ugd/39cb9d_375a5f26acf94f50ae98e51494eb906b.pdf?index=true
    • https://s3.amazonaws.com/wuniku/35319724887.pdf
    • https://832c8a8d-f05d-46e3-9166-97d9de82ace4.filesusr.com/ugd/432509_a87650083aba48069531f2c862b3b32f.pdf?index=true
    • https://fc06435f-e709-4c80-b59d-96fa470c1a13.filesusr.com/ugd/bdc04d_63eea10312c346c08e29750413e5a1c7.pdf?index=true
    • https://s3.amazonaws.com/ximupuv/maduvi.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d7e4.bin
f1e2f278b5f5edc3107b23def85ed3d02400ef5532ea2be55f8faa442e18adb0		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD7E4 5252 bytes
font_01_sfnt_off0000e9a9.bin
1f776a9bf2102655f6a1f22ed00432e1322692feb60d76753cc651b350ad7f23		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE9A9 12024 bytes

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