Malicious PDF — malware analysis report

Static analysis result for SHA-256 1b2b7d5ccaa7c14d…

MALICIOUS

PDF

36.0 KB Created: 2020-09-18 18:32:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c925ec2274d1f2ada90dc8e4edda71d6 SHA-1: 1e8d2429d3bd051ce3d7020237676b6f4b0cee32 SHA-256: 1b2b7d5ccaa7c14d56b8b1a0b7713588b348a27ad8ab36508d3938f867833062
152 Risk Score

Malware Insights

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

The PDF contains a mass of external links, masquerading as a grammar worksheet, with the primary malicious link pointing to a known redirector. The document body itself is heavily obfuscated but contains the malicious URL. The ML classifier strongly indicated 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.link/wix?keyword=conjuguemos+grammar+worksheet+preterite+tense+regular+verbs+answers
    • https://cdn.shopify.com/s/files/1/0460/7918/0964/files/lemon_tree_worksheet_esl.pdf
    • https://cdn.shopify.com/s/files/1/0435/4631/2863/files/21817535795.pdf
    • https://cdn.shopify.com/s/files/1/0436/9501/4056/files/46250192326.pdf
    • https://cdn.shopify.com/s/files/1/0431/8307/9584/files/1133072569.pdf
    • https://cdn.shopify.com/s/files/1/0481/2937/6407/files/siop_features_checklist.pdf
    • https://11896bba-f9bb-4c8f-ae78-31dc543d824a.filesusr.com/ugd/135178_578d265135464233a8fcf3a8f0950906.pdf?index=true
    • https://045589e0-8df5-40f8-ac04-ed02ebc69b08.filesusr.com/ugd/8c0e65_06401ec62b3344ad9b6fc808413a229b.pdf?index=true
    • https://f304a04a-de71-424f-a1c4-53739fe1c2df.filesusr.com/ugd/66f7a0_67585b24420646ccb034d1de779b904c.pdf?index=true
    • https://338b4140-b0ca-4705-a12c-7d6cacfe3066.filesusr.com/ugd/314c35_4df00b81b80d48cc95f2aecbf14ed47f.pdf?index=true
    • https://192d5321-2acc-4810-af99-4a6f7e28f084.filesusr.com/ugd/87b9a8_5bddd7fda0df44ac9fddc8d4d2777bcf.pdf?index=true
    • https://d51b215f-117b-4824-bc2c-e00e697574f2.filesusr.com/ugd/21b4a7_dd5edaf102df4e7ba1b365def784aad2.pdf?index=true
    • 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_off00004bac.bin
9b030e0126876eb82f1b880f5e3c547e1997b8bcf3e2fd3a6bf46c180a134569
pdf-font-stream PDF embedded font (sfnt) at offset 0x4BAC 5572 bytes
font_01_sfnt_off00005e88.bin
473154f057523e7dd35eb1cdd2e370e522e179b577b6922376ef20983fdb3ccf
pdf-font-stream PDF embedded font (sfnt) at offset 0x5E88 10844 bytes