Malicious PDF — malware analysis report

Static analysis result for SHA-256 806b51b884fac537…

MALICIOUS

PDF

42.6 KB Created: 2020-08-14 10:44:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 175c7508242db65c730499a09e231b28 SHA-1: 44d933cb6e3433a31934b00a9a89543ab004b020 SHA-256: 806b51b884fac537bc5d025b37365bd45ba0bd0ae1d1badef989ce6773f9f35b
152 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many of which point to external PDFs hosted on various domains. One of these links, https://ttraff.ru/pify?keyword=nims+is+100+test+answers, is identified as a known malicious redirector. The document body, though heavily obfuscated, also contains this URL, suggesting the primary purpose is to redirect the user to malicious infrastructure. The ML classifier strongly supports the malicious nature of this PDF.

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.ru/pify?keyword=nims+is+100+test+answers
    • http://xeren.roaring20s.blog/uploads/1/3/0/8/130813528/f1c08cf02056.pdf
    • http://files.letmebegreatchildrensyoga.com/uploads/1/3/1/3/131380295/luvipaxikudi.pdf
    • http://xotezosa.sauveriegel.com/uploads/1/3/2/8/132814930/pasalowavulikum-tidunaga-ludobewugajov-pemofojexaze.pdf
    • http://tometu.fcstnebraska.com/uploads/1/3/1/1/131164250/904894.pdf
    • https://cdn.shopify.com/s/files/1/0432/5687/3128/files/8652622529.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/37144816260.pdf
    • https://cdn.shopify.com/s/files/1/0432/4343/8244/files/cours_d_algorithme_et_exercices_corrigs.pdf
    • https://cdn.shopify.com/s/files/1/0433/0012/6880/files/xidaloxeme.pdf
    • https://cdn.shopify.com/s/files/1/0435/2029/5064/files/charlotte_s_web_script.pdf
    • https://cdn.shopify.com/s/files/1/0428/8947/8307/files/vatijejitutuwe.pdf
    • https://cdn.shopify.com/s/files/1/0428/9308/2783/files/mitaba.pdf
    • https://cdn.shopify.com/s/files/1/0444/6345/6423/files/convertidor_analgico_digital.pdf
    • https://cdn.shopify.com/s/files/1/0435/6662/9032/files/gomefovip.pdf
    • https://cdn.shopify.com/s/files/1/0427/9776/0668/files/guxis.pdf
    • https://cdn.shopify.com/s/files/1/0432/6372/1637/files/74188937085.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_off00006a31.bin
173af71421b0915aed6b8775a95950d2e238a00afa8091acd525dd9ac5038fa9
pdf-font-stream PDF embedded font (sfnt) at offset 0x6A31 5052 bytes
font_01_sfnt_off00007b5d.bin
f797b7665a60f2463b42f363c974a306b62edddf3ef3b7a28a404a49a65b3ca7
pdf-font-stream PDF embedded font (sfnt) at offset 0x7B5D 10204 bytes