Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b4a92494acdb48b…

MALICIOUS

PDF

43.7 KB Created: 2020-08-29 04:22:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3cbbdeee81f44d24b135bd1589155d73 SHA-1: 24f4da950f8f7e582b43a4259d7475aa35621813 SHA-256: 5b4a92494acdb48b5b8d492f8aa017839dde8b4d8ada24c2dabfedcc00b7021f
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded links, many of which point to external resources, suggesting a link farm or redirection attempt. One prominent URL, https://ttraff.ru/wix?keyword=usmle+rx+qbank+pdf, is flagged as a malicious redirector. The document body, though heavily obfuscated, contains references to 'USMLE rx qbank pdf', indicating a lure to disguise the malicious intent. The ML classifier also strongly flagged this PDF as malicious.

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/wix?keyword=usmle+rx+qbank+pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://cdn.shopify.com/s/files/1/0431/8865/0141/files/rasexibasaxod.pdf
    • https://cdn.shopify.com/s/files/1/0428/2440/1063/files/kiwekitozemibemoleluju.pdf
    • https://cdn.shopify.com/s/files/1/0433/7424/8101/files/40760302334.pdf
    • https://cdn.shopify.com/s/files/1/0427/5381/8790/files/53910807509.pdf
    • https://cdn.shopify.com/s/files/1/0427/9749/8535/files/95651166067.pdf
    • https://static.usrfiles.com/ugd/b8c837_7beb640a4f9040a49920aa0e436c6a55.pdf
    • https://static.usrfiles.com/ugd/b8c837_fc64a79bd1e343d5a31e14258736a2f3.pdf
    • https://static.usrfiles.com/ugd/b8c837_1f17923b4a0d416fbc5000765ac83152.pdf
    • https://cdn.shopify.com/s/files/1/0431/6545/0391/files/dedozeda.pdf
    • https://cdn.shopify.com/s/files/1/0432/4432/2978/files/49988046078.pdf
    • https://cdn.shopify.com/s/files/1/0433/2231/0811/files/nabutovibaxunakazejij.pdf
    • https://cdn.shopify.com/s/files/1/0428/8148/2919/files/93209981849.pdf
    • https://cdn.shopify.com/s/files/1/0429/3397/7255/files/87116341641.pdf
    • https://cdn.shopify.com/s/files/1/0431/7226/6150/files/labojojurezofijujagupol.pdf
    • https://cdn.shopify.com/s/files/1/0429/8991/2218/files/coca_cola_brown_coloru_song.pdf
    • https://cdn.shopify.com/s/files/1/0432/3554/1151/files/tranny_s_in_ct.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/
    • http://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005fb3.bin
5dd0bdafcaa09e67b1699c4ca542b3e1e39f06ddc69d37c6c4c5c0367efd1782		 pdf-font-stream PDF embedded font (sfnt) at offset 0x5FB3 5576 bytes
font_01_sfnt_off00007284.bin
a36eee06fef6ce219692c4ec918276ac99413e4fd1e3666e4031624f9289d620		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7284 1800 bytes
font_02_sfnt_off00007b11.bin
c7d651dc0fa4c91f250cb5b63ca0bcc4e1e149de3fd5b5973f296d5b2774c808		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7B11 10976 bytes

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