Malicious PDF — malware analysis report

Static analysis result for SHA-256 a231b40cdfca0c0e…

MALICIOUS

PDF

38.8 KB Created: 2020-07-28 08:54:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c73bad7c5f4e654316f68bafb1e171b2 SHA-1: 38b88d0a50388711e6af3d62bdec11a9139ddf04 SHA-256: a231b40cdfca0c0e26b288ea0e585eed0d2d2d556a1ff471f13b1b470d90b997
152 Risk Score

Malware Insights

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

The PDF contains a significant number of external links, with one identified as a malicious redirector. The ML classifier strongly indicated maliciousness. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs. The primary attack vector appears to be a link farm designed to lure users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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.
  • 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=into+the+unknown+sheet+music+frozen+pdf
    • http://files.rainkraft.in/uploads/1/3/1/4/131452740/zoxuraki_votujegi_mumor.pdf
    • http://files.fincacafe.com/uploads/1/3/0/7/130740069/f1019.pdf
    • http://files.alwayshelpful.org/uploads/1/3/1/4/131437241/7137734.pdf
    • https://cdn.shopify.com/s/files/1/0427/9032/2342/files/83470280679.pdf
    • https://cdn.shopify.com/s/files/1/0431/9143/5422/files/zanekon.pdf
    • https://cdn.shopify.com/s/files/1/0433/4757/4943/files/9081226860.pdf
    • https://cdn.shopify.com/s/files/1/0431/6397/5835/files/lixidixokawus.pdf
    • https://cdn.shopify.com/s/files/1/0433/6146/8574/files/95715434724.pdf
    • https://cdn.shopify.com/s/files/1/0431/0522/2822/files/natedufujizejivakuden.pdf
    • https://cdn.shopify.com/s/files/1/0436/2836/3939/files/91340618619.pdf
    • https://cdn.shopify.com/s/files/1/0433/6635/0998/files/nakisubabumoki.pdf
    • https://cdn.shopify.com/s/files/1/0430/8657/7818/files/gilufojegivaw.pdf
    • https://cdn.shopify.com/s/files/1/0431/5601/3205/files/11317911726.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005a0a.bin
66e9c4bbe4204203b6851b54343b4eb8b7acc279b33a8fb093765fe69202f332
pdf-font-stream PDF embedded font (sfnt) at offset 0x5A0A 5180 bytes
font_01_sfnt_off00006b98.bin
b9f47e528d73e7e12b7a415a4b89ac5c0f9c75b9c09cded673ec3042d9fb227b
pdf-font-stream PDF embedded font (sfnt) at offset 0x6B98 10140 bytes