Malicious PDF — malware analysis report

Static analysis result for SHA-256 efc33f5d5aacb4c4…

MALICIOUS

PDF

55.0 KB Created: 2020-08-31 03:25:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3107ccf4325f328850a63b115f8451ce SHA-1: 684f7968c399163eeafae834b832e5328256e42e SHA-256: efc33f5d5aacb4c4e49a77958c0a053a3d5e25b2540d5d3100f40e32f92c8a38
152 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a malicious redirector link, specifically pointing to 'ttraff.ru'. The document body, though heavily obfuscated, contains text that appears to be a lure ('My homework lesson 1'). The PDF also exhibits characteristics of a link farm, with numerous embedded URLs, many pointing to 'static.usrfiles.com', suggesting an attempt to manipulate search engine results or distribute content through a large number of linked documents. The ML classifier also 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.ru/wix?keyword=my+homework+lesson+1
    • https://static.usrfiles.com/ugd/83e24f_c37e6032649743148b7c58c42e177a06.pdf
    • https://static.usrfiles.com/ugd/6da380_c9c4757ed26d4c3f83564ce096b252f3.pdf
    • https://static.usrfiles.com/ugd/b8bbd7_118e7554839f4a5694257f394ab9bf09.pdf
    • https://static.usrfiles.com/ugd/b8c837_76caa8574d1f42748c249e5a7a8c8f39.pdf
    • https://static.usrfiles.com/ugd/b8c837_4a0a25b781d44df9a49f8fe19a98fd19.pdf
    • https://static.usrfiles.com/ugd/a4d998_b0a8ecfcf7de4311b0e448a61ec2583c.pdf
    • https://static.usrfiles.com/ugd/b8c837_6f42116102f64ca3866508ef0553202b.pdf
    • https://static.usrfiles.com/ugd/4d935e_132fe0422cee4cdeb84f43d0b3feb527.pdf
    • https://cdn.shopify.com/s/files/1/0431/3877/7249/files/business_analyst_books.pdf
    • https://cdn.shopify.com/s/files/1/0432/2505/5389/files/28135291158.pdf
    • https://cdn.shopify.com/s/files/1/0429/7709/9935/files/harvard_style_referencing_document.pdf
    • https://cdn.shopify.com/s/files/1/0437/3191/0821/files/nupufudimibikatew.pdf
    • https://cdn.shopify.com/s/files/1/0429/4865/7318/files/siwem.pdf
    • https://static.usrfiles.com/ugd/b28561_b7652c8c081a49d194ee46ab98934fac.pdf
    • https://static.usrfiles.com/ugd/b8c837_d99d9feb1f144681b9db795ef12f9348.pdf
    • https://static.usrfiles.com/ugd/e4bc37_cdd84d6ee7bc48bc8a76dc32115788a9.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00007914.bin
f74fbd477a351d8157395dac8c84a041738c5baa0d28c770d547904bb49baa96		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7914 4688 bytes
font_01_sfnt_off000088e1.bin
86cb5940fc4a11097f4652e54b00b0f988236cc829b45c341ace6e7416a46984		 pdf-font-stream PDF embedded font (sfnt) at offset 0x88E1 10220 bytes
font_02_sfnt_off0000ac12.bin
bf23ea22eb0e49ca753a433c96634d27055d16f44e34ef027f79059ecc810d74		 pdf-font-stream PDF embedded font (sfnt) at offset 0xAC12 16060 bytes
font_03_sfnt_off0000c0b0.bin
0d0f64e27578eb124b8bc81c7eceacdd166e22eddd95c81328e9fbd7de2a6333		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC0B0 4324 bytes

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