Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef819b23f1332148…

MALICIOUS

PDF

44.6 KB Created: 2020-07-09 07:02:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-09-07
MD5: 5d4c8265d94df59dfa458117297a78d4 SHA-1: 06cbfc4b961bf3d7d4820fb3fe71f96043868c24 SHA-256: ef819b23f13321480b42a551dd757e0ea0b23371d78c357fa0d0327f084d6d86
194 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains a large number of embedded links, many of which point to PDF files hosted on various domains. One critical heuristic identified a link to a known malicious redirector infrastructure, suggesting a phishing or malware distribution attempt. The document body, though partially corrupted, contains text related to 'maths worksheets for 5th grade' and a URL that aligns with the redirector link, reinforcing the lure.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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://ttraff.com/wb?keyword=maths%20worksheets%20for%205th%20grade In PDF document text
    • http://files.orangevalleycreations.com/uploads/1/3/1/3/131383510/bujofaketuwomidabej.pdfIn PDF document text
    • http://files.missdc.org/uploads/1/3/1/8/131872096/netolol-tonawevajijaw.pdfIn PDF document text
    • http://files.exmouthcaninecentre.co.uk/uploads/1/3/1/0/131070379/612343e61.pdfIn PDF document text
    • http://files.dianakayeart.com/uploads/1/3/1/4/131454238/gamawu-vuzetujox-vumasixupaloka-nuvavov.pdfIn PDF document text
    • http://files.mymoonmalas.com/uploads/1/3/2/6/132681316/f8954ce2662.pdfIn PDF document text
    • http://files.morroandjasp.com/uploads/1/3/0/9/130969375/wojerodijudo.pdfIn PDF document text
    • http://files.anniepercussion.com/uploads/1/3/2/7/132740321/disatibe.pdfIn PDF document text
    • http://files.jocelynpearsoncoaching.com/uploads/1/3/0/7/130739401/fetijag_feboxe_fezufod.pdfIn PDF document text
    • http://files.sillassenhalf.com/uploads/1/3/0/9/130969555/bevijidu.pdfIn PDF document text
    • http://files.azsundriescompany.com/uploads/1/3/0/7/130775292/8175673.pdfIn PDF document text
    • http://files.barrons-conferences.com/uploads/1/3/1/4/131409170/3066792.pdfIn PDF document text
    • http://files.leftyyang.com/uploads/1/3/0/9/130969514/9168938.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://gubuwujuje.files.wordpress.com/2020/07/67165373382.pdfIn PDF document text
    • https://luragekid.files.wordpress.com/2020/06/13504641435.pdfIn PDF document text
    • https://xezerak.files.wordpress.com/2020/06/refug.pdfIn PDF document text
    • https://movugabopiru.files.wordpress.com/2020/06/1344531102.pdfIn PDF document text
    • https://famexuzin.files.wordpress.com/2020/06/wosubulozezinam.pdfIn PDF document text
    • https://xefipun.files.wordpress.com/2020/06/1470812037.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/65294746239.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/nitopufekuriwuk.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/91300886864.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/50398535586.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/13879903487.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/mijafovaginidobu.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/1204107997.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_off00007131.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7131 5056 bytes
SHA-256: 5faf63c26a3c98e554252c008abca4997aa2a10c7fe2fefc5f040e460f302bb8
font_01_sfnt_off00008291.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8291 9976 bytes
SHA-256: 7b1d2a87b58a0237e0c3eb742031093d81c3dd271c8e6f273a33e57029d15b86