Malicious PDF — malware analysis report

Static analysis result for SHA-256 b996391e56c5109a…

MALICIOUS

PDF

37.1 KB Created: 2020-07-14 09:05:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-09-24
MD5: 58afc0a104de4a0feafeee30582c03ee SHA-1: fff27646ce83ae7a470e1949f0a71383fd40fcff SHA-256: b996391e56c5109a728f0f936e11c9608ac9de5de282a149ade0bdf1a191f567
194 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many pointing to external PDF files hosted on various domains, indicating a link farm. One critical heuristic identified a link to a known malicious redirector infrastructure. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create documents for SEO poisoning or to mask malicious links.

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.ru/wb?keyword=esl%20both%20either%20neither%20worksheets In PDF document text
    • http://files.boissys.com/uploads/1/3/1/3/131398141/814da7d8376c424.pdfIn PDF document text
    • http://files.taniamackey.com/uploads/1/3/1/3/131379231/0622a877a9e0.pdfIn PDF document text
    • http://files.bisonsbikes.com/uploads/1/3/2/6/132682754/3729316.pdfIn PDF document text
    • http://files.slmspto.org/uploads/1/3/2/6/132680932/1493219.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://cdn.shopify.com/s/files/1/0429/7133/2767/files/44869521767.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/zetuvoveluganimuwejipas.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/9277/8901/files/sexeratokujezimobod.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0432/0608/2717/files/70594421430.pdfIn PDF document text
    • https://memibenamefu.files.wordpress.com/2020/06/dewesusuvikanexod.pdfIn PDF document text
    • https://takojezo.files.wordpress.com/2020/06/54380819878.pdfIn PDF document text
    • https://fipoxek.files.wordpress.com/2020/07/25704933600.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0432/9324/5590/files/naxodapi.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0434/9100/0472/files/ladunojilered.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0429/2476/9436/files/varapef.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/40573574370.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/6856/3355/files/rorizozuguvapopej.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/2314/6909/files/litotiguvomiwada.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 3

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_off00005683.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5683 4604 bytes
SHA-256: 7f9f373a90f5d1380d06cd16806efcd893a8b495e48019153f2460b2c6879e64
font_01_sfnt_off00006623.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6623 9596 bytes
SHA-256: 75652450182302b9ee092cf877ebef787e53a86e7481d620ad23de540b993bfa

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