Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bae77a90ac2e4fa…

MALICIOUS

PDF

40.5 KB Created: 2020-08-29 16:59:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 364e12df6d5be9f94f196fd63d4f1876 SHA-1: f27ff9fce7aa60a00135a56b9013ca0863cdd1dd SHA-256: 4bae77a90ac2e4fa4bd9b3d9e9ce575037c6fbb03fcfdd6ad1c85a04c038bee5
152 Risk Score

Malware Insights

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

The PDF contains a high number of embedded links, many pointing to Shopify domains, but one critical link directs to a known malicious redirector. The ML classifier also strongly indicated maliciousness. The document body, though heavily obfuscated, contains the malicious URL and appears to be a lure related to 'rounding large numbers worksheet'.

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/wix?keyword=rounding+large+numbers+worksheet
    • https://cdn.shopify.com/s/files/1/0433/3525/4171/files/19704591361.pdf
    • https://cdn.shopify.com/s/files/1/0431/6535/2102/files/85876122062.pdf
    • https://cdn.shopify.com/s/files/1/0430/8205/5842/files/how_to_delete_branch_on_github.pdf
    • https://cdn.shopify.com/s/files/1/0433/4436/3678/files/chundari_penne_song_free.pdf
    • https://static.usrfiles.com/ugd/eb5a6a_d20bebf895ca481aa642a63a477b5470.pdf
    • https://cdn.shopify.com/s/files/1/0430/2720/2205/files/3651811154.pdf
    • https://cdn.shopify.com/s/files/1/0430/7563/3306/files/93413051576.pdf
    • https://cdn.shopify.com/s/files/1/0438/1815/6192/files/aseptic_technique_microbiology.pdf
    • https://cdn.shopify.com/s/files/1/0434/6911/1448/files/jodusakajurunomazu.pdf
    • https://cdn.shopify.com/s/files/1/0428/9318/1095/files/talakaxedezagoti.pdf
    • https://cdn.shopify.com/s/files/1/0430/8975/6311/files/adobe_creative_cloud_update_failed_error.pdf
    • https://cdn.shopify.com/s/files/1/0434/5469/3529/files/how_to_install_borderlands_2_reborn.pdf
    • https://cdn.shopify.com/s/files/1/0433/8958/3514/files/kefegaxoxu.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/xuvoba.pdf
    • https://cdn.shopify.com/s/files/1/0433/0799/1208/files/tutorials_in_introductory_physics_homework_solutions.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_off00005f29.bin
20724aafa7de6250f5f3a5a424df09091ca182d260c08ddc850f92374d549f10
pdf-font-stream PDF embedded font (sfnt) at offset 0x5F29 5540 bytes
font_01_sfnt_off000071e6.bin
39fdf7b097a4197050223f6294ceba345599c5d59e4476e22f4e9d08ee45bdd4
pdf-font-stream PDF embedded font (sfnt) at offset 0x71E6 10364 bytes