Malicious PDF — malware analysis report

Static analysis result for SHA-256 a87b906b1c8c4b63…

MALICIOUS

PDF

79.7 KB Created: 2021-03-21 22:06:43 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 16b9105d86601761aacc93a364ea3cef SHA-1: bab95fddea101ee0f79047a09cb9682fd691bd8a SHA-256: a87b906b1c8c4b6354e211c53d38fd2fab9218e32be36e3276e2b5207bd3e57c
254 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains numerous embedded links, many of which point to redirector infrastructure like 'crophysi.ru'. Heuristics indicate this is a link farm designed to lure users to malicious sites, likely for phishing or to download further malware. The ML classifier and ClamAV detection strongly support a malicious classification.

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.
  • 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.
  • 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/wix?keyword=apostle+guillermo+maldonado+pdf In PDF document text
    • http://resimpub.com/suzozzrmg7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4444114/normal_5fe8aad093cb3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4372681/normal_603d60b3924ad.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4381546/normal_5fcc202a2ef73.pdfIn PDF document text
    • http://samettemiz.xyz/31908942530jnwxs.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4375896/normal_5fe607bb1ce37.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4403946/normal_60486bddd257c.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/nevovumowa/what_is_the_approach_that_scrum_encourages_when_a_team_determined.pdfIn PDF document text
    • https://s3.amazonaws.com/zagubip/tapolinad.pdfIn PDF document text
    • https://a121017b-3fb3-450c-9156-48dd71a9bf80.filesusr.com/ugd/07625c_7857e2b20a3e48c9b146e06094edf27c.pdf?index=trueIn PDF document text
    • https://98350ace-7ac4-4f38-a9d9-579fdad8050b.filesusr.com/ugd/9b2d9b_fa6470b6c077483aad10abc45d5efc75.pdf?index=trueIn PDF document text
    • https://1e35b969-1f99-48dc-8aa8-d0fb9638bdc8.filesusr.com/ugd/970baa_b658cc78790f4c4f9c9b0f449d999725.pdf?index=trueIn PDF document text
    • https://9e705916-5bde-4eb8-be9b-8b3e910fbaf8.filesusr.com/ugd/c7a620_1e216712b3af4834afaa75b62e5ed92e.pdf?index=trueIn PDF document text
    • https://88211235-bf86-4d40-a6ec-a052db2f682e.filesusr.com/ugd/94e5ef_df1ac6f0942942d49437da752229709a.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/likerajatob/48169379456.pdfIn PDF document text
    • https://s3.amazonaws.com/patilawasu/tifoseva.pdfIn PDF document text
    • https://0ef2f354-78a3-4528-990c-72f69c86fc6a.filesusr.com/ugd/6a0da6_ff514fa7351844a8950af8a9d1501632.pdf?index=trueIn PDF document text
    • https://1eb42bdc-3da6-4b32-b75f-4382f1721f8e.filesusr.com/ugd/35474d_1b3f9eceaf474287aa6c2fe4b4296238.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/bogeguva/frankenstein_mary_shelley_famous_quotes.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_off0000fa1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA1A 5348 bytes
SHA-256: 8434acede17c5c773cf16f054395ae2eab33bb44e76f23abfe5fa843799d23df
font_01_sfnt_off00010c32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C32 11168 bytes
SHA-256: ef6c1b1f7e9b7d38205eddbcc076fd840c8c2175786885c922dfaf92ede8f13d