Malicious PDF — malware analysis report

Static analysis result for SHA-256 51338c1667f0f5c4…

MALICIOUS

PDF

48.5 KB Created: 2020-08-14 18:44:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2026-05-07
MD5: 21f24525bcfde95e95bc2c2c2ccde689 SHA-1: 4b00e9f2df653e731b97bd63cd35a88227e612d3 SHA-256: 51338c1667f0f5c4b6adbd42cc903a25091916412b472ec2e32a79def9117be6
194 Risk Score

Malware Insights

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

The PDF contains a link farm designed to mimic educational resources, with the primary malicious link redirecting to a suspicious domain. The ML classifier strongly indicated maliciousness. The document body, though heavily obfuscated, contains the malicious URL and several benign-looking PDF links, likely to establish a facade of legitimacy.

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/pify?keyword=sound+energy+worksheets In PDF document text
    • http://files.mcapitalmgt.com/uploads/1/3/1/8/131859042/366a75f5caa71.pdfIn PDF document text
    • http://files.blackberrycreek.org/uploads/1/3/0/8/130813837/veletigowek-pefigojinosifim-zafokozeve.pdfIn PDF document text
    • http://files.patrickdixon.net/uploads/1/3/1/4/131483336/xevupoxawuwogafinobi.pdfIn PDF document text
    • http://files.studio22ws.com/uploads/1/3/0/8/130874030/b7aad9f0d8.pdfIn PDF document text
    • http://files.det13ksc.com/uploads/1/3/1/8/131871852/8b423d2355c84.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/1/0431/8475/0743/files/bpp_acca_f1_study_text.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0435/5633/9871/files/91127814890.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/3485/4051/files/5760152641.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/4995/1138/files/89928277282.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0435/4686/9911/files/98926921082.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0435/6630/1343/files/cessna_172r_poh.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/3799/0813/files/40820626497.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/2693/1099/files/pdf_files_download_sample.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0447/3444/7770/files/stab_bonus_pokemon.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0430/7533/8389/files/furupizavol.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/5916/7900/files/conjunctions_worksheets_for_grade_5_with_answers.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0432/6152/6166/files/vupopo.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0427/4615/1078/files/vakizajidibipume.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_off00007e50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7E50 5208 bytes
SHA-256: 17d1f55db561fbb89a4aac02148c7e8ab819895a163a68a2df668d5beb04373e
font_01_sfnt_off00009013.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9013 10664 bytes
SHA-256: 6eedd4a174f250c4962b135f280126fe25efced974c8acc604888f0ae7c01615