Malicious PDF — malware analysis report

Static analysis result for SHA-256 1b516089ccceb765…

MALICIOUS

PDF

41.5 KB Created: 2020-08-12 22:13:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 344a3e33fd9a03baa884ae5a03cc1bce SHA-1: 8fae419a5efb18ad980488b69066e11944c74e81 SHA-256: 1b516089ccceb765b863c438c863a20a9e9963b27741f3532e048a12d876a8c2
152 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many pointing to external PDF files, characteristic of a link farm. One prominent link directs to a known malicious redirector. The document body, though heavily obfuscated, contains text related to multiplication worksheets, likely a lure. The ML classifier strongly indicates maliciousness.

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=2+digit+by+1+digit+multiplication+worksheets+pdf+grade+3
    • http://files.teamequistar.com/uploads/1/3/1/3/131380469/jukuvemolore-nopatavurifuwo.pdf
    • http://files.buhundpuppies.com/uploads/1/3/0/8/130873864/6623328.pdf
    • http://vuxolazaw.peregrinosysusletras.net/uploads/1/3/1/0/131070450/3603386.pdf
    • https://cdn.shopify.com/s/files/1/0432/3006/8894/files/60685470370.pdf
    • https://cdn.shopify.com/s/files/1/0433/8073/6151/files/dozokefaba.pdf
    • https://cdn.shopify.com/s/files/1/0430/2992/1943/files/94462086945.pdf
    • https://cdn.shopify.com/s/files/1/0431/0050/4217/files/arteria_cerebral_media_derecha.pdf
    • https://cdn.shopify.com/s/files/1/0448/2295/4141/files/abscesso_cerebral_tratamento.pdf
    • https://cdn.shopify.com/s/files/1/0428/3393/6547/files/91693122152.pdf
    • https://cdn.shopify.com/s/files/1/0431/1220/2389/files/5512143110.pdf
    • https://cdn.shopify.com/s/files/1/0433/7729/5521/files/7367608792.pdf
    • https://cdn.shopify.com/s/files/1/0430/3929/3589/files/pakipotefeno.pdf
    • https://cdn.shopify.com/s/files/1/0431/0505/8976/files/xalafo.pdf
    • https://cdn.shopify.com/s/files/1/0428/1496/3868/files/xorax.pdf
    • https://cdn.shopify.com/s/files/1/0432/7532/1499/files/74601580749.pdf
    • https://cdn.shopify.com/s/files/1/0434/1517/5335/files/binary_search_tree_class_c.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_off0000612f.bin
648b84cb767af8e72fbc22ecc36de7da1bb616af34e999fcdf1284108b74fe4c
pdf-font-stream PDF embedded font (sfnt) at offset 0x612F 6220 bytes
font_01_sfnt_off00007642.bin
4274ceb20d26694ebbc63e5a3c0d4d7611d38b67bb176b60562b33a790418b78
pdf-font-stream PDF embedded font (sfnt) at offset 0x7642 10060 bytes