Malicious PDF — malware analysis report

Static analysis result for SHA-256 a61b35db6d045435…

MALICIOUS

PDF

49.8 KB Created: 2020-08-31 05:55:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c536b369558c95ee3e2bf0b101a511b6 SHA-1: 4a3674f92351ce689ee284000cdd875d712616db SHA-256: a61b35db6d0454350b00e3ca51097ef2c73be2d2c41282a12143f28f7600b7c2
152 Risk Score

Malware Insights

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

The PDF contains a link to a known malicious redirector, https://ttraff.cc/wix?keyword=examen+de+segundo+bimestre+quinto+grado, which is likely used to deliver further malicious content. The document also exhibits characteristics of a PDF link farm, with numerous links to external PDFs hosted on static.usrfiles.com. The ML classifier strongly flagged this PDF as malicious, supporting the conclusion that it is designed for malicious redirection.

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.cc/wix?keyword=examen+de+segundo+bimestre+quinto+grado
    • https://static.usrfiles.com/ugd/455f95_f1b8be5ba7794abcbd190b3a7b14d987.pdf
    • https://static.usrfiles.com/ugd/b8c837_111f842161c24db69370aa173d83e0fb.pdf
    • https://static.usrfiles.com/ugd/e42ee3_554ccb0d5fd645b9ad89f4066031a824.pdf
    • https://static.usrfiles.com/ugd/1cfe37_9c43b7c8e0df4fa8b409134512afed0a.pdf
    • https://static.usrfiles.com/ugd/3649d2_bdc913cf61f24601b637689970a3c0bf.pdf
    • https://static.usrfiles.com/ugd/b8c837_823acaa553614b9ba5458ec17e847cb4.pdf
    • https://static.usrfiles.com/ugd/e02969_0bac1d81ea4e428081283964434a074e.pdf
    • https://static.usrfiles.com/ugd/87b9a8_7bd45c971ca04df2b0e43ac7696a03ab.pdf
    • https://static.usrfiles.com/ugd/451461_900432f556954b6da27b597810506e58.pdf
    • https://static.usrfiles.com/ugd/b444d4_0efb41dbfeb84930915ab1000339fbf0.pdf
    • https://static.usrfiles.com/ugd/98857b_e07a9ad771d64ff793c74b45338eacb3.pdf
    • https://static.usrfiles.com/ugd/b8c837_e340b4e0341b4c08a2f918c0e687e228.pdf
    • https://static.usrfiles.com/ugd/b8c837_5bf50ae1afd24b6fb38718fd7279e402.pdf
    • https://static.usrfiles.com/ugd/73cb9e_53688037988f4673b591e65cadf529e2.pdf
    • https://static.usrfiles.com/ugd/d7ba0f_f4b69db5cd7540c5897ed4481faabc3e.pdf
    • https://static.usrfiles.com/ugd/b8c837_a25d2ea2402347baa32c25210f26d2f1.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000071d3.bin
407874ac4df062595804f5156442904cb0b495f8d41a9e354f25aa0b52759fc6		 pdf-font-stream PDF embedded font (sfnt) at offset 0x71D3 5288 bytes
font_01_sfnt_off000083a7.bin
3bdbd19d47f75f3e77db86550aa34f2674fde988a41de6b5d04d19ccdc79844f		 pdf-font-stream PDF embedded font (sfnt) at offset 0x83A7 11980 bytes
font_02_sfnt_off0000aa69.bin
7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71		 pdf-font-stream PDF embedded font (sfnt) at offset 0xAA69 4324 bytes

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