Malicious PDF — malware analysis report

Static analysis result for SHA-256 51079c8ae2da60dc…

MALICIOUS

PDF

80.7 KB Created: 2021-05-23 03:05:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 4e5bd40be28190fc37b8f884dc8c7e2e SHA-1: 8ee6035474bb0abaf4cacfdf4f8e0394570fefa6 SHA-256: 51079c8ae2da60dcb464dea944fa7f29b0939aac9e8d7134020898268902f025
136 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains a significant number of external links, many pointing to other PDFs, which is indicative of an SEO link farm or a distribution mechanism for further malicious content. The primary URL, https://fokemale.ru/strik?utm_term=architecture+sketching+exercises+pdf, appears to be an SEO redirector used to lure users. While no scripts were explicitly extracted, the PDF structure and heuristic firings strongly suggest malicious intent related to content distribution and potentially user redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://fokemale.ru/strik?utm_term=architecture+sketching+exercises+pdf PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4414353/normal_5fdd2e123af82.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450424/normal_6043c14fac4b5.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4476285/normal_5fc98f7f427a4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4410190/normal_605f831f66046.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4379964/normal_5febe5f86a456.pdfIn PDF document text
    • https://sorolaxubamabu.weebly.com/uploads/1/3/0/7/130739744/kapalegivo-bapefebewep-wusov-jufol.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4497093/normal_603852055772a.pdfIn PDF document text
    • https://lukuxafibufogi.weebly.com/uploads/1/3/5/4/135400428/1078500.pdfIn PDF document text
    • https://buruwezixefekiw.weebly.com/uploads/1/3/0/7/130738548/f303c4066904.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4449411/normal_5febbe8a5d0c6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4392210/normal_601b1e35f0ad8.pdfIn PDF document text
    • https://betetaguzom.weebly.com/uploads/1/3/2/3/132303315/luvivaxevan_fiditiwu_binok.pdfIn PDF document text
    • https://kabixiwuvilaz.weebly.com/uploads/1/3/2/6/132681231/7434787.pdfIn PDF document text
    • https://nexawukuvinu.weebly.com/uploads/1/3/4/5/134578226/farofud.pdfIn PDF document text
    • https://xoxudepibedewem.weebly.com/uploads/1/3/5/3/135317482/6556417.pdfIn PDF document text
    • https://ganubidorebe.weebly.com/uploads/1/3/2/7/132740923/9264893.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/kofabube/how_to_use_a_ratchet_belt.pdfIn PDF document text
    • https://s3.amazonaws.com/muvojugejoxip/tufogafibi.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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ff02.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF02 5296 bytes
SHA-256: 8b77bf0327141e73b433ca73261462637c6816d0b14e036f91ce65d7d1c6ef6c
font_01_sfnt_off0001110e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1110E 10832 bytes
SHA-256: d917cf251fc56a872f44369e2382d198b22686d750d966724b137d2a52c355ef

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