Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa2f8e948cdb67bb…

MALICIOUS

PDF

41.0 KB Created: 2020-08-31 07:26:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: fd668a773cc756c89d1b286ae1bf8cba SHA-1: 68a537447d6e450b970c0385e82af1cf5f96e0f3 SHA-256: aa2f8e948cdb67bb930ca0a082a793e320e90f34f06ef259f1fd3ea0c7ad60f0
152 Risk Score

Malware Insights

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

The PDF contains a heuristic firing for a malicious redirector link, specifically pointing to 'https://ttraff.ru/wix?keyword=conjunctions+worksheet+for+class+4'. The document body, though heavily obfuscated, also contains this URL and references a 'conjunctions worksheet for class 4', suggesting a lure. The presence of numerous other links to static.usrfiles.com, while marked as benign, indicates a link farm strategy. The ML classifier strongly supports the malicious verdict.

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=conjunctions+worksheet+for+class+4
    • https://static.usrfiles.com/ugd/b8c837_067fd5a819054fd1a5076994dc77ec65.pdf
    • https://static.usrfiles.com/ugd/73c254_8a1d36b161fb4035891c604085da6136.pdf
    • https://static.usrfiles.com/ugd/b8c837_8012811e613d4442b9bae7f5fa8b8c84.pdf
    • https://static.usrfiles.com/ugd/87a178_4a621dd2178a4ba6b14d056a5732f0c8.pdf
    • https://static.usrfiles.com/ugd/405339_8ce1b1b837ae46749f243f68e4b11dbb.pdf
    • https://static.usrfiles.com/ugd/b8c837_245ffa7f2bc344569f12a01034556000.pdf
    • https://static.usrfiles.com/ugd/c1615c_b098261fc69340a0b0a44e79de6031cb.pdf
    • https://static.usrfiles.com/ugd/314c35_c13715eb04d34468a6f07695bdf4c83d.pdf
    • https://static.usrfiles.com/ugd/b8c837_694db9700031449888a3771616668c3d.pdf
    • https://static.usrfiles.com/ugd/b8c837_bf741a8d945f49c5a699f7df45f2abdf.pdf
    • https://static.usrfiles.com/ugd/b8c837_17772981c6da43f3936d302466e8daf8.pdf
    • https://cdn.shopify.com/s/files/1/0438/4548/4706/files/acc_aha_guidelines_carotid_artery_disease.pdf
    • https://cdn.shopify.com/s/files/1/0432/6883/3436/files/ruvebelexobukazadaji.pdf
    • https://cdn.shopify.com/s/files/1/0427/8360/4903/files/cbse_ugc_net_july_2018_answer_key.pdf
    • https://cdn.shopify.com/s/files/1/0434/8831/3510/files/clash_royale_hacks_no_survey.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/71860998709.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_off00006159.bin
abaa9609b91d4bf4254129d454f1139541b62d24101414cf3f7f2c7163485367		 pdf-font-stream PDF embedded font (sfnt) at offset 0x6159 5196 bytes
font_01_sfnt_off00007315.bin
92a6443c38b2aac2d6dec9d53ae5903e7ef4b49da4a9e7898954ca6d77dd2eba		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7315 10692 bytes

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