Malicious PDF — malware analysis report

Static analysis result for SHA-256 b37c8e994d311d58…

MALICIOUS

PDF

46.5 KB Created: 2020-07-23 10:22:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-09-04
MD5: 0cb8b86261192b4ed7ce8bf1e81ff46d SHA-1: dd7ff562160fb96ab911d2ab38a65903d2674a93 SHA-256: b37c8e994d311d58f73bfca1421a4fe745e59813bf797b0ded986a568dcbb1c1
194 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded links, with one specifically pointing to a known malicious redirector. The heuristic firings indicate this is a link farm designed to distribute malicious content. The ML classifier strongly supports the malicious verdict. No scripts were extracted, but the primary attack pattern is the distribution of 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.com/wb?keyword=phonic%20sounds%20a%20to%20z%20chart%20pdf In PDF document text
    • http://files.westfielddentalpa.com/uploads/1/3/0/7/130775942/bavef_kezujuwusuk_javexolizepun.pdfIn PDF document text
    • http://files.basketballpantheon.com/uploads/1/3/1/4/131453396/e20797fd39.pdfIn PDF document text
    • http://files.brave458.com/uploads/1/3/0/7/130775561/vedebik.pdfIn PDF document text
    • http://files.leadershippasadena.org/uploads/1/3/1/4/131483025/pukoxisiv-wunuguzop-bolot.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/1/0428/9835/8432/files/1741554469.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0437/4256/0407/files/juruvunafajovaremepaku.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/85755015361.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/xodujanizovu.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/4677/2629/files/farowid.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0434/1284/8790/files/20906353438.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0436/9409/6539/files/84793163628.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0434/1065/3338/files/89443609169.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0427/8714/3839/files/68690323435.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/3976/9254/files/jevuxunit.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0434/1573/2376/files/59671231326.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0427/5165/6102/files/fazugalumajisafoj.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0432/5045/0600/files/21985998730.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0432/5516/9186/files/7621699235.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0430/7773/0464/files/64540199891.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_off00007826.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7826 5024 bytes
SHA-256: 48ac82e9e2bab2adb81b930d51ff4b1751a58c199f10e1032c1dfdfd72bb4b21
font_01_sfnt_off00008929.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8929 10400 bytes
SHA-256: ed4e777443ea96f076ca4d7524a2c09384787a74317b4525c5cdef6b299fb0ea