Malicious PDF — malware analysis report

Static analysis result for SHA-256 51f591629eaf672c…

MALICIOUS

PDF

72.5 KB Created: 2020-07-12 22:57:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-08-25
MD5: c027e681ee4f606309112c249f88b9b3 SHA-1: 32232da48c041de30a5a1214cf863f17aa9b3e9e SHA-256: 51f591629eaf672cf0c6f12116520ab754a3b57f009e7943275c65cd1d5b10f2
194 Risk Score

Malware Insights

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

The PDF file contains numerous embedded links, with a critical heuristic firing for PDF_MALICIOUS_REDIRECTOR_LINK indicating a link to a known malicious redirector. Another critical heuristic, PDF_SEO_LINK_FARM, highlights the presence of a large number of external PDF links, suggesting a link farm or redirection strategy. The ML classifier also strongly flagged this PDF as malicious. The document body is heavily obfuscated, but the presence of the wkhtmltopdf application name and a date suggests it was generated programmatically.

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=books%20about%20meditation%20pdf In PDF document text
    • http://files.melrockworld.com/uploads/1/3/1/4/131406934/31cf418.pdfIn PDF document text
    • http://files.sewsewquilt.com/uploads/1/3/1/3/131380045/ee664f.pdfIn PDF document text
    • http://files.professorjavas.us/uploads/1/3/2/7/132710630/jagosuroguxid_borapovukuverep.pdfIn PDF document text
    • http://files.stamellstring.com/uploads/1/3/0/9/130969984/4003678.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/1/0429/1756/0473/files/kujuved.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0427/9477/8791/files/54811910508.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0427/6623/7852/files/32994925778.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/64255738852.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/8861538602.pdfIn PDF document text
    • https://xexusugemavu.files.wordpress.com/2020/07/netejisabovukiz.pdfIn PDF document text
    • https://jidematapaf.files.wordpress.com/2020/06/84281630449.pdfIn PDF document text
    • https://vipikewef.files.wordpress.com/2020/06/75057203426.pdfIn PDF document text
    • https://kugigoke149047822.files.wordpress.com/2020/06/gewujoxifuvepit.pdfIn PDF document text
    • https://nuxezobexet.files.wordpress.com/2020/07/90340095738.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0430/3015/1330/files/lamere.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/pitoparejiki.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/76102764406.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/37237973095.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/tipibag.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0430/8772/4704/files/naxopi.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_off0000dddc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDDC 5192 bytes
SHA-256: 0556bc4fabf390f90b49f5573ce4626ecb75089dd35976dc2897d99ae1c203a7
font_01_sfnt_off0000ef75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF75 10920 bytes
SHA-256: 2e4a91b7d5801f3aa2095989afa0c83c4c97aa28c68c15619bd3792f2e483bd7